Pharmaceutical compositions comprising cyclosporins

ABSTRACT

Pharmaceutical compositions comprising a cyclosporin, e.g. Ciclosporin or [Nva] 2  -Ciclosporin, in &#34;microemulsion pre-concentrate&#34; and microemulsion form. The compositions typically comprise (1.1) a C 1-5  alkyl or tetrahydrofurfuryl di- or partial-ether of a low molecular weight mono- or poly-oxy-alkane diol, e.g. Transcutol or Glycofurol, as hydrophilic component. Compositions are also provided comprising a cyclosporin and (1.1) and, suitably, also a saccharide monoester, e.g. raffinose or saccharose monolaurate. Dosage forms include topical formulations and, in particular, oral dosage forms.

This is a continuation of application Ser. No. 07/680,211, filed Apr. 4,1991 now abandoned which in turn is a continuation of application Ser.No. 07/406,656, filed Sep. 13, 1989, now abandoned.

The present invention relates to novel galenic formulations comprising acyclosporin as active ingredient.

The cyclosporins comprise a class of structurally distinctive, cyclic,poly-N-methylated endecapeptides, commonly possessing pharmacological,in particular immunosuppressive, anti-inflammatory and/or anti-parasiticactivity. The first of the cyclosporins to be isolated was the naturallyoccurring fungal metabolite Ciclosporin or Cyclosporine, also known ascyclosporin A and commercially available under the Registered Trade MarkSANDIMMUN® or SANDIMMUNE®. Ciclosporin is the cyclosporin of formula A.##STR1## wherein -MeBmt- represents theN-methyl-(4R)-4-but-2E-en-1-yl-4-methyl-(L) threonyl residue of formulaB ##STR2## in which -x-y- is --CH═CH-- (trans).

As the parent of the class Ciclosporin has so far received the mostattention. The primary area of clinical investigation for Ciclosporinhas been as an immunosuppressive agent, in particular in relation to itsapplication to recipients of organ transplants, e.g. heart, lung,combined heart-lung, liver, kidney, pancreatic, bone-marrow, skin andcorneal transplants and, in particular, allogenic organ transplants. inthis field Ciclosporin has achieved a remarkable success and reputation.

At the same time, applicability of Ciclosporin to various autoimmunediseases and to inflammatory conditions, in particular inflammatoryconditions with an aetiology including an autoimmune component such asarthritis (for example rheumatoid arthritis, arthritis chronicaprogrediente and arthritis deformans) and rheumatic diseases, has beenintensive and reports and results in vitro, in animal models and inclinical trials are wide-spread in the literature. Specific auto-immunediseases for which Ciclosporin therapy has been proposed or appliedinclude, autoimmune hematological disorder (including e.g. hemolyticanaemia, aplastic anaemia, pure red cell anaemia and idiopathicthrombocytopaenia), systemic lupus erythematosus, polychondritis,sclerodoma, Wegener granulamatosis, dermatomyositis, chronic activehepatitis, myasthenia gravis, psoriasis, Steven-Johnson syndrome,idiopathic sprue, autoimmune inflammatory bowel disease (including e.g.ulcerative colitis and Crohn's disease) endocrine opthalmopathy, Gravesdisease, sarcoidosis, multiple sclerosis, primary billiary cirrhosis,juvenile diabetes (diabetes mellitus type I), uveitis (anterior andposterior), keratoconjunctivitis sicca and vernal keratoconjunctivitis,interstitial lung fibrosis, psoriatic arthritis and glomerulonephritis(with and without nephrotic syndrome, e.g. including idiopathicnephrotic syndrome or minimal change nephropathy).

Further areas of investigation have been potential applicability as ananti-parasitic, in particular anti-protozoal agent, with possible usessuggested including treatment of malaria, coccidiomycosis andschistosomiasis and, yet more recently, use as an agent for reversing orabrogating anti-neoplastic agent resistance in tumours and the like.

Since the original discovery of ciclosporin, a wide variety of naturallyoccurring cyclosporins have been isolated and identified and manyfurther non-natural cyclosporins have been prepared by total- orsemi-synthetic means or by the application of modified culturetechniques. The class comprised by the cyclosporins is thus nowsubstantial and includes, for example, the naturally occurringcyclosporins A through Z [c.f. Traber et al. 1, Helv. Chim. Acta. 60,1247-1255 (1977); Traber et al. 2, Helv. Chim. Acta. 65 no. 162,1655-1667 (1982); Kobel et al., Europ. J. Applied Microbiology andBiotechnology 14, 273-240 (1982); and von Wartburg et al., Progress inAllergy, 38, 28-45 (1986)], as well as various non-natural cyclosporinderivatives and artificial or synthetic cyclosporins including the socalled dihydro-cyclosporins (in which the moiety -x-y- of the -MeBmt-residue (Formula B above) is saturated to give -x-y-=--CH₂ --CH₂ --;derivatised cyclosporins (e.g. in which a further substituent isintroduced at the α-carbon atom of the sarcosyl residue at the3-position of the cyclosporin molecule); cyclosporins in which the-MeBmt- residue is present in isomeric form (e.g. in which theconfiguration across positions 6' and 7' of the -MeBmt- residue is cisrather than trans); and cyclosporins wherein variant amino acids areincorporated at specific positions within the peptide sequence,employing e.g. the total synthetic method for the production ofcyclosporins developed by R. Wenger-see e.g. Traber 1, Traber 2 andKobel loc. cit.; U.S. Pat. Nos. 4,108,985, 4,210,581 and 4,220,641;European Patent Publication Nos. 0 034 567 and 0 056 782; InternationalPatent Publication No. WO 86/02080; Wenger 1, Transp. Proc. 15, Suppl.1:2230 (1983); Wenger 2, Angew. Chem. Int. Ed., 24, 77 (1985); andWenger 3, Progress in the Chemistry of Organic Natural Products 50, 123(1986).

The class comprised by the cyclosporins is thus now very large indeedand includes, for example, [Thr]² -, [Val]² -, [Nva]² - and [Nva]²-[Nva]⁵ -Ciclosporin (also known as cyclosporins C,D, G and Mrespectively), [3-0-acyl-MeBmt]¹ -Ciclosporin (also known as cyclosporinA acetate), [Dihydro-MeBmt]¹ -[Val]² -Ciclosporin (also known asdihydrocyclosporin D), [(D)Fluoromethyl-Sar]³ -Ciclosporin, [(D)Ser]⁸-Ciclosporin, [MeIle]¹¹ -Ciclosporin, [(D)MeVal]¹¹ -Ciclosporin (alsoknown as cyclosporin H), [MeAla]⁶ -Ciclosporin, [(D)Pro]³ -Ciclosporinand so on.

(In accordance with now conventional nomenclature for cyclosporins,these are defined by reference to the structure of Ciclosporin (i.e.Cyclosporin A). This is done by first indicating the amino acid residuespresent which differ from those present in Ciclosporin (e.g. "[(D)Pro]³" to indicate that the cyclosporin in question has a -(D)Pro- ratherthan -Sar- residue at the 3-position) and then applying the term"Ciclosporin" to characterise remaining residues which are identical tothose present in Ciclosporin. Individual residues are numbered startingwith the residue -MeBmt- or -dihydroMeBmt- in position 1.)

Very many of these further cyclosporins exhibit comparablepharmaceutical utility to Ciclosporin or more specific utility, forexample activity particularly in reversing tumor resistance tocytostatic therapy, and proposals for their application as therapeuticagents abound in the literature.

Despite the very major contribution which Ciclosporin has made, inparticular to the areas of organ transplant and the therapy ofautoimmune diseases, difficulties encountered in providing moreeffective and convenient means of administration as well as the reportedoccurrence of undesirable side reactions, in particular nephrotoxicreaction, have been obvious serious impediments to its wider use orapplication. The cyclosporins are characteristically highly hydrophobic.Proposed liquid formulations, e.g. for oral administration ofcyclosporins, have hitherto been based primarily on the use of ethanoland oils or similar excipients as carrier media. Thus the commerciallyavailable Ciclosporin drink-solution employs ethanol and olive oil ascarrier medium in conjunction with labrafil as a surfactant--see e.g.U.S. Pat. No. 4,388,307. Use of the drink-solution and similarcompositions as proposed in the art is however accompanied by a varietyof difficulties.

First, the necessity to use oils or oil based carriers may lend thepreparations an unpleasant taste or otherwise reduce palatability, inparticular for the purposes of long-term therapy. These effects can bemasked by presentation in gelatin capsule form. However, in order tomaintain the cyclosporin in solution, the ethanol content has to be kepthigh. Evaporation of the ethanol, e.g. from capsules or from otherforms, e.g. when opened, results in the development of a cyclosporinprecipitate. Where such compositions are presented in e.g. soft gelatinencapsulated form, this particular difficulty necessitates packaging ofthe encapsulated product in an air-tight compartment, for example anair-tight blister or aluminium-foil blister-package. This in turnrenders the product both bulky and more expensive to produce. Thestorage characteristics of formulations as aforesaid are far from ideal.

Bioavailability levels achieved using existing oral cyclosporin dosagesystems are also low and exhibit wide variation between individuals,individual patient types and even for single individuals at differenttimes during the course of therapy. Thus reports in the literatureindicate that currently available therapy employing the commerciallyavailable Ciclosporin drink solution provides an average absolutebioavailability of ca. 30% only, with marked variation betweenindividual groups, e.g. between liver (relatively low bioavailability)and bone-marrow (relatively high bioavailability) transplant recipients.Reported variation in bioavailability between subjects has varied fromanything between one or a few percent for some patients to as much as90% or more for others. And as already noted, marked change inbioavailability for individuals with time is frequently observed.

To achieve effective immunosuppressive therapy, cyclosporin blood orblood serum levels have to be maintained within in a specified range.The required range can in turn vary, depending on the particularcondition being treated, e.g. whether therapy is to prevent transplantrejection or for the control of an autoimmune disease, and on whether ornot alternative immunosuppressive therapy is employed concomitantly withcyclosporin therapy. Because of the wide variations in bioavailabilitylevels achieved with conventional dosage forms, daily dosages needed toachieve required blood serum levels will also vary considerably fromindividual to individual and even for a single individual. For thisreason it is necessary to monitor blood/blood-serum levels of patientsreceiving cyclosporin therapy at regular and frequent intervals.Monitoring of blood/blood-serum levels, which is generally performed byRIA or equivalent immunoassay technique, e.g. employing monoclonalantibody based technology, has to be carried out on a regular basis.This is inevitably time consuming and inconvenient and addssubstantially to the overall cost of therapy.

Beyond all these very evident practical difficulties lies the occurrenceof undesirable side reactions already alluded to, observed employingavailable oral dosage forms.

Several proposals to meet these various problems have been suggested inthe art, including both solid and liquid oral dosage forms. Anoverriding difficulty which has however remained is the inherentinsolubility of the cyclosporins, e.g. Ciclosporin, in aqueous media andhence provision of a dosage from which can contain cyclosporins insufficiently high concentration to permit convenient use and yet meetthe required criteria in terms of bioavailability, e.g. enablingeffective resorption from the stomach or gut lumen and achievement ofconsistent and appropriately high blood/blood-serum levels.

The particular difficulties encountered in relation to oral dosagingwith cyclosporins have inevitably led to restrictions in the use ofcyclosporin therapy for the treatment of relatively less severe orendangering disease conditions. A particular area of difficulty in thisrespect has been the adoption of cyclosporin therapy in the treatment ofautoimmune diseases and other conditions affecting the skin, for examplefor the treatment of atopic dermatitis and psoriasis and, as also widelyproposed in the art, for hair growth stimulation, e.g. in the treatmentof alopecia due to ageing or disease.

Thus while oral Ciclosporin therapy has shown that the drug is ofconsiderable potential benefit to patients suffering e.g. frompsoriasis, the risk of side-reaction following oral therapy hasprevented common use. Various proposals have been made in the art forapplication of cyclosporins, e.g. Ciclosporin, in topical form and anumber of topical delivery systems have been described. Attempts attopical application have however failed to provide any demonstrablyeffective therapy. A means of topical application providing effectivedermal delivery and useful, e.g. for the treatment of psoriasis, wouldeffectively make cyclosporin therapy available to, what is, a majorpatient population at need.

By the present invention there are provided novel cyclosporin galenicformulations in the form of a micro-emulsion pre-concentrate and/orbased on the use of particular solvent media as hereinafter defined,which meet or substantially reduce difficulties in cyclosporin, e.g.Ciclosporin, therapy hitherto encountered in the art. In particular ithas been found that the compositions of the invention permit thepreparation of solid, semi-solid and liquid compositions containing acyclosporin in sufficiently high concentration to permit, e.g.convenient oral administration, while at the same time achievingimproved efficacy, e.g. in terms of bioavailability characteristics.

More particularly it has been found that compositions in accordance withthe present invention enable effective cyclosporin dosaging withconcomitant enhancement of resorption/bioavailability levels, as well asreduced variability in resorption/bioavailability levels achieved bothfor individual patients receiving cyclosporin therapy as well as betweenindividuals. By application of the teachings of the present inventioncyclosporin dosage forms are obtainable providing reduced variablilityin achieved cyclosporin blood/blood serum levels between dosages forindividual patients as well as between individuals/individual patientgroups. The invention thus enables reduction of cyclosporin dosagelevels required to achieve effective therapy. In addition it permitscloser standardisation as well as optimisation of on-going daily dosagerequirements for individual subjects receiving cyclosporin therapy aswell as for groups of patients undergoing equivalent therapy.

By closer standardisation of individual patient dosaging rate andblood/blood-serum level response, as well as dosaging and responseparameters for patient groups, monitoring requirements may be reduced,thus substantially reducing the cost of therapy.

By reduction of required cyclosporin dosaging/standardisation ofachieved bio-availability characteristics, the present invention alsooffers a means permitting reduction in the occurrence of undesirableside-effects, in particular nephrotoxic reaction, in patients undergoingcyclosporin therapy.

In relation to topical application, the present invention furtherenables the preparation of novel galenical formulations comprising acyclosporin, e.g. Ciclosporin, as active ingredient and permittingimproved treatment for autoimmune diseases affecting the skin, inparticular, of dermatological disease involving morbid proliferationand/or keratinisation of the epidermis, especially of psoriasis andatopic dermatosis. Topically applicable compositions in accordance withthe invention are also of use in the treatment of alopecia, e.g. for usein the promotion of hair growth.

In a first aspect, the present invention specifically providespharmaceutical compositions comprising a cyclosporin as activeingredient, which compositions are in the form of a "microemulsionpre-concentrate".

By the term "microemulsion pre-concentrate" as used herein is meant asystem capable on contacting with, e.g. addition to, water of providinga microemulsion. The term microemulsion as used herein is used in itsconventionally accepted sense as a non-opaque or substantiallynon-opaque colloidal dispersion comprising water and organic componentsincluding hydrophobic (lipophilic) organic components. Microemulsionsare identifiable as possessing one or more of the followingcharacteristics. They are formed spontaneously or substantiallyspontaneously when their components are brought into contact, that iswithout substantial energy supply, e.g. in the absence of heating or theuse of high shear equipment or other substantial agitation. They exhibitthermodynamic stability. They are monophasic. They are substantiallynon-opaque, i.e. are transparent or opalescent when viewed by opticalmicroscopic means. In their undisturbed state they are opticallyisotropic, though an anisotropic structure may be observable using e.g.x-ray technique.

Microemulsions comprise a dispersed or particulate (droplet) phase, theparticles of which are of a size less than 2,000 Å, hence their opticaltransparency. The particles of a microemulsion may be spherical, thoughother structures are feasible, e.g. liquid crystals with lamellar,hexagonal or isotropic symmetries. Generally, micro-emulsions comprisedroplets or particles having a maximum dimension (e.g. diameter) of lessthan 1,500 Å, e.g. typically from 100 to 1,000 Å.

(For further discussion of the characteristics of microemulsions see,e.g. Rosof, Progress in Surface and Membrane Science, 12, 405 et seq.Academic Press (1975); Friberg, Dispersion Science and Technology, 6(3), 317 et seq. (1985); and Muller et al. Pharm. Ind., 50 (3), 370 etseq. (1988)).

From the foregoing it will be understood that the "microemulsionpre-concentrates" of the invention are galenic systems comprising acyclosporin as active ingredient capable of forming a microemulsion,spontaneously or substantially spontaneously on contact with wateralone.

Pharmaceutical "microemulsion pre-concentrate" compositions comprisingcyclosporins as active ingredient are novel. Accordingly in one aspectthe present invention provides:

A) A pharmaceutical composition comprising a cyclosporin as activeingredient, which composition is a "microemulsion pre-concentrate".

(The term "pharmaceutical composition" as used herein and in theaccompanying claims is to be understood as defining compositions ofwhich the individual components or ingredients are themselvespharmaceutically acceptable, e.g. where oral administration is foreseen,acceptable for oral use and, where topical administration is foreseen,topically acceptable.)

In addition to the cyclosporin active ingredient, the "microemulsionpre-concentrate" compositions of the invention will appropriatelycomprise:

1) a hydrophilic phase;

2) a lipophilic phase; and

3) a surfactant.

The cyclosporin is carried in the lipophilic phase. Suitably both thehydrophilic and lipophilic phases will serve as carrier medium.

"Microemulsion pre-concentrates" of the invention are of a typeproviding o/w (oil-in-water) microemulsions. As will be appreciatedhowever, compositions in accordance with (A) may contain minorquantities of water or otherwise exhibit fine structural featurescharacteristic of microemulsions, e.g. of o/w or w/o (water-in-oil)type. The term "microemulsion pre-concentrate" as used herein isaccordingly to be understood as embracing such possibilities.

Microemulsions obtained on contacting the "microemulsionpre-concentrate" compositions of the invention with water or otheraqueous medium exhibit thermodynamic stability, that is they will remainstable at ambient temperatures, e.g. without clouding or regularemulsion size droplet formation or precipitation, over prolonged periodsof time. (It will of course be understood that, to obtain amicroemulsion, adequate water will be required. While the upper limit ofdilution is not critical, a dilution of 1:1, preferably 1:5 parts per"weight ("microemulsion pre-concentrate": H₂ O) or more will generallybe appropriate.) Preferably, on contacting with water, the"microemulsion pre-concentrate" compositions of the invention arecapable of providing microemulsions which remain stable at ambienttemperatures, e.g. as evidenced by absence of any optically observableclouding or precipitation, over periods of at least 2 hours, morepreferably at least 4 hours, most preferably at least 12 to 24 hours.Microemulsions obtainable from "microemulsion pre-concentrates" of theinvention, e.g. at dilutions as indicated above, will preferably have anaverage particle size of less than about 1,500 Å, more preferably ofless than about 1,000 or 1,100 Å, e.g. down to about 150 or 200 Å.

Especially preferred in accordance with the present invention arecompositions as defined under (A) in which the hydrophilic phasecomprises:

1.1. A pharmaceutically acceptable C₁₋₅ alkyl or tetrahydrofurfuryl di-or partial-ether of a low molecular weight mono- or poly-oxy-alkanediol;or

1.2. 1,2-propyleneglycol.

Suitable components (1.1.) are, e.g. di- or partial-, especiallypartial-, -ethers of mono- or poly-, especially mono- or di-,-oxy-alkanediols comprising from 2 to 12, especially 4 carbon atoms.Preferably the mono- or poly-oxy-alkanediol moiety is straight-chained.Especially suitable for use in accordance with the invention are di- orpartial-ethers of formula I

    R.sub.1 --[O--(CH.sub.2).sub.2 ].sub.x --OR.sub.2          (I)

wherein

R₁ is C₁₋₅ alkyl or tetrahydrofurfuryl,

R₂ is hydrogen, C₁₋₅ alkyl or tetrahydrofurfuryl, and

x is an integer of from 1 to 6, especially from 1 to 4, most especiallyabout 2.

Particularly preferred for use in accordance with the invention arepartial ethers as defined above, e.g. products of formula I, wherein R₂is hydrogen.

C₁₋₅ alkyl moieties in the above defined ethers may be branched orstraight chain, e.g. including methyl, ethyl, n-propyl, i-propyl,n-butyl and t-butyl groups.

Such ethers are known products and commercially available or may beproduced analogously to the known products. Especially preferredproducts of formula I for use in relation to the present invention arethose known and commercially available under the trade names TRANSCUTOLand COLYCOFUROL.

Transcutol is the compound diethyleneglycol monoethyl ether of formulaI, wherein R₁ =C₂ H₅, R₂ =H and x=2.

COLYCOFUROL, also known as tetrahydrofurfuryl alcohol polyethyleneglycol ether or α-(tetrahydrofuranyl)-ω-hydroxypoly(oxy-1,2-ethanediyl)has the formula I wherein R₁ = ##STR3## R₂ =H and x has an average valueof from 1 to 2. It has an average molecular weight of ca. 190; a b.p. offrom ca. 80°-100° C. (at 40N/m²), a density of ca. 1.070-1.090 g/cm³ (at20° C.); a hydroxy value of ca. 300-400; a refractive index of ca.1.4545 (sodium D line, 589 mm) (at 40° C.); and a viscosity of ca. 8-18mN s/m² (at 20° ). (c.f. "Handbook of Pharmaceutical Excipients,published by American Pharmaceutical Association/ The PharmaceuticalSociety of Great Briatin (1986), p. 127 and Fiedler, "Lexikon derHilfstoffe", 3rd edition (1989), p. 577.)

The precise properties of COLYCOFUROL vary according to relative purity.Thus lower quality grades contain significant amounts oftetrahydrofurfuryl alcohol and other impurities. For the purposes of thepresent invention COLYCOFUROL 75, designating a product meeting theabove physical data and for which the fraction having the formula Iabove in which x=1-2 amounts to a minimum of 95%, is preferred.

Use of components defined under (1.1.) and (1.2.) above has inparticular been found to provide compositions in accordance with (A) inwhich the hydrophilic phase is especially well suited as cyclosporincarrier medium, e.g. in which the hydrophilic phase enablescyclosporin-loading of the composition, adequate for convenienttherapeutic dosaging, e.g. for oral administration.

Compositions in accordance with (A) comprising components as definedunder (1.1.) and /or (1.2.) as hydrophilic phase may of courseadditionally include one or more further ingredients as hydrophilicphase component. Preferably however any additional components willcomprise materials in which the cyclosporin active ingredient issufficiently soluble, such that the efficacy of the hydrophilic phase ascyclosporin carrier medium is not materially impaired. Examples ofpossible additional hydrophilic phase components are lower (e.g. C₁₋₅)alkanols, in particular ethanol.

In an especially preferred embodiment the hydrophilic phase ofcompositions defined under (A) will consist or consist essentially ofcomponents as defined under (1.1.) or (1.2.) above, in particularTRANSCUTOL, COLYCOFUROL and/or 1,2-propylene glycol. Most suitably theywill consist or consist essentially of either components (1.1.) orcomponent (1.2.).

Compositions in accordance with (A) comprising a component (1.1),especially COLYCOFUROL, are of particular interest in that they are welladapted for presentation in soft gelatin encapsulated form. Suchcompositions have, in accordance with the invention, also been found toexhibit surprisingly advantageous stability, e.g. as evidenced inlong-term stability tests at normal and elevated temperatures. Suchcompositions are thus particularly well suited to meet difficultiescommonly encountered in transport and storage of drug products,including long term storage at the user end, e.g. in hospitals, clinicsand like facilities.

Compositions defined under (A) additionally comprise a lipophilic phase(2).

Suitable components for use as lipophilic phase include anypharmaceutically acceptable solvent which is non-miscible with theselected hydrophilic phase, e.g. as defined under (1.1.) or (1.2.). Suchsolvents will appropriately be devoid or substantially devoid ofsurfactant function. Especially suitable components for use aslipophilic phase components (2) are, e.g.:

Fatty acid triglycerides, preferably medium chain fatty acidtriglycerides. Especially suitable are neutral oils, e.g. neutral plantoils, in particular fractionated coconut oils such as known andcommercially available under the trade name MIGLYOL (c.f. Fiedler, loc.cit. pp. 808-809), including the products:

MIGLYOL 810: a fractionated coconut oil comprising caprylic-capric acidtriglycerides and having a molecular weight : ca. 520. Fatty acidcomposition=C₆ max. 2%, C₈ ca. 65-75%, C₁₀ ca. 25-35%, C₁₂ max. 2%; acidno.=ca. 0.1; saponification no.=ca. 340-360; iodine no.=max. 1;

MIGLYOL 812: a fractionated coconut oil comprising caprylic-capric acidtriglycerides and having a molecular weight=ca. 520. Fatty acidcomposition=C₆ max. ca. 3%, C₈ ca. 50-65%, C₁₀ ca. 30-45%, C₁₂ max. 5%;acid no.=ca. 0.1; saponification no.=ca. 330-345; iodine no.=max. 1;

MIGLYOL 818: a caprylic-capric-linoleic acid triglyceride having amolecular weight=ca. 510. Fatty acid composition=C₆ max. 3, C₈ ca.45-60, C₁₀ ca. 25-40, C₁₂ ca. 2-5, C_(18:2) ca. 4-6; acid no.=max. 0.2;saponification no.=ca. 315-335, iodine no.=max. 10; and

CAPTEX 355(¹) a caprylic-capric acid triglyceride. Fatty acidcontent=caproic ca. 2%, caprylic ca. 55%, capric ca. 42%. Acid no.=max.0.1; saponification no. =ca. 325-340; iodine no.=max. 0.5.

Also suitable are caprylic-capric acid triglycerides such as known andcommercially available under the trade name MYRITOL (c.f. Fiedler loc.cit., p. 834) including the product MYRITOL 813 which has an acidno.=max. 1, a saponification no.=ca. 340-350 and an iodine no.=ca. 0.5.

Further suitable products of this class are CAPMUL MCT(¹), CAPTEX 300(¹)and CAPTEX 800(¹), NEOBEE M5(²) and MAZOL 1400(³).

((1)=Capital City Products, PO. Box 569, Columbus, Ohio, USA.(2)=Stepan, PVO Dept., 100 West Hunter Ave., Maywood, N.J. 07607, USA.(3)=Mazer Chemicals, 3938 Porett Drive, Gurnee, Ill., USA).)

Especially preferred as lipophilic phase component is the productMIGLYOL 812.

Compositions in accordance with the invention defined under (A) furthercomprise a pharmaceutically acceptable surfactant (3). The surfactantcomponent may comprise (3.1.) hydrophilic or (3.2..) lipophilicsurfactants, or mixtures thereof. Especially preferred are non-ionichydrophilic and non-ionic lipophilic surfactants. Examples of suitablehydrophilic surfactants for use as surfactant components are e.g.:

3.1.1. Reaction products of natural or hydrogenated vegetable oils andethylene glycol, i.e. polyoxyethylene glycolated natural or hydrogenatedvegetable oils, for example polyoxyethylene glycolated natural orhydrogenated castor oils. Such products may be obtained in known manner,e.g. by reaction of a natural or hydrogenated castor oil or fractionsthereof with ethylene oxide, e.g. in a molar ratio of from about 1:35 toabout 1:60, with optional removal of free polyethyleneglycol componentsfrom the product, e.g. in accordance with the methods disclosed inGerman Auslegeschriften 1,182,388 and 1,518,819. Especially suitable arethe various tensides available under the trade name CREMOPHOR.Particularly suitable are the products CREMOPHOR RH 40 having asaponification no. ca. 50-60, an acid no.=<1, an iodine no.=<1, a watercontent (Fischer)=<2%, an n_(D) ⁶⁰ =ca. 1,453-1,457 and an HLB=ca.14-16; CREMOPHOR RH 60 having a saponification no.=ca. 40-50, an acidNo. =<1, an iodine no.=<1, a water content (Fischer)=ca. 4.5-5.5%, ann_(D) ²⁵ =ca. 1.453-1,457 and an HLB=ca. 15-17; and CREMOPHOR EL havinga molecular weight (by steam osmometry)=ca. 1630, a saponificationno.=ca. 65-70, an acid no.=ca. 2, an iodine no.=ca. 28-32 and an n_(D)²⁵ =ca. 1.471 (c.f. Fiedler loc. cit. pp. 326-327). Also suitable foruse in this category are the various tensides available under the tradename Nikkol, e.g. Nikkol HC0-60. The said product NIKKOL HC0-60 is areaction product of hydrogenated castor oil and ethylene oxideexhibiting the following characteristics: Acid no.=ca. 0.3;Saponification no.=ca. 47.4; Hydroxy value=ca. 42.5. pH (5%)=ca. 4.6;Color APHA=ca. 40; m.p.=ca. 36.0° C.; Freezing point=ca. 32.4° C.; H₂ Ocontent (%, KF)=ca. 0.03;

3.1.2. Polyoxyethylene-sorbitan-fatty acid esters e.g. mono- andtrilauryl, palmityl, stearyl and oleyl esters e.g. of the type known andcommercially available under the trade name TWEEN (c.f. Fiedler, loc.cit. pp. 1300-1304) including the products TWEEN

20 [polyoxyethylene(20)sorbitanmonolaurate],

40 [polyoxyethylene(20)sorbitanmonopalmitate],

60 [polyoxyethylene(20)sorbitanmonostearate],

80 [polyoxyethylene(20)sorbitanmonooleate],

65 [polyoxyethylene(20)sorbitantristearate],

85 [polyoxyethylene(20)sorbitantrioleate],

21 [polyoxyethylene(4)sorbitanmonolaurate],

61 [polyoxyethylene(4)sorbitanmonostearate], and

81 [polyoxyethylene(5)sorbitanmonooleate].

Especially preferred products of this class for use in the compositionsof the invention are the above products TWEEN 40 and TWEEN 80;

3.1.3. Polyoxyethylene fatty acid esters, for example polyoxyethylenestearic acid esters of the type known and commercially available underthe trade name MYRJ (c.f. Fiedler, loc. cit., p. 834) as well aspolyoxyethylene fatty acid esters known and commercially available underthe trade name CETIOL HE. (c.f. Fiedler, loc. cit., p. 284); anespecially preferred product of this class for use in the compositionsof the invention is the product MYRJ 52 having a D²⁵ =ca. 1.1., m.p.=ca.40°-44° C., an HLB=ca. 16.9., an acid no.=ca. 0-1 and a saponificationno.=ca. 25-35;

3.1.4. Polyoxyethylene-polyoxypropylene co-polymers, e.g. of the typeknown and commercially available under the trade names PLURONIC andEMKALYX (c.f. Fiedler, loc. cit., pp. 956-958). An especially preferredproduct of this class for use in the compositions of the invention isthe product PLURONIC F68;

3.1.5. Polyoxyethylene-polyoxypropylene block co-polymers, e.g. of thetype known and commercially available under the trade name POLOXAMER(c.f. Fiedler, loc. cit., pp. 959). An especially suitable product ofthis class for use in the compositions of the invention is the productPOLOXAMER 188;

3.1.6. Dioctylsuccinate, dioctylsodiumsulfosuccinate,di-[2-ethylhexyl]-succinate or sodium lauryl sulfate;

3.1.7. Phospholipids, in particular lecithins (c.f. Fiedler, loc. cit.,pp. 731-733). Lecithins suitable for use in the compositions of theinvention include, in particular, soya bean lecithins;

3.1.8. Propylene glycol mono- and di-fatty acid esters such as propyleneglycol dicaprylate, propylene glycol dilaurate, propylene glycolhydroxystearate, propylene glycol isostearate, propylene glycol laurate,propylene glycol ricinoleate, propylene glycol stearate and so forth(c.f. Fiedler, loc. cit., pp. 1013 et seq.). Especially preferred ispropylene glycol caprylic-capric acid diester as known and commerciallyavailable under the trade name MIGLYOL 840 (c.f. Fiedler, loc. cit., p.809). MIGLYOL 840 has a fatty acid content=C₆ max. ca. 3%, C₈ ca.65-80%, C₁₀ ca. 15-30%, C₁₂ max. 3%. Acid no.=max. 0.1, iodine no.=ca.320-340, iodine no.=max. 1; and

3.1.9. Bile salts, e.g. alkali metal salts, for example sodiumtaurocholate.

Examples of suitable lipophilic surfactants for use as surfactantcomponent are, e.g.:

3.2.1. Trans-esterification products of natural vegetable oiltriglycerides and polyalkylene polyols. Such trans-esterificationproducts are known from the art and may be obtained e.g. in accordancewith the general procedures described in U.S. Pat. No. 3,288,824. Theyinclude transesterification products of various natural (e.g.non-hydrogenated) vegetable oils for example, maize oil, kernel oil,almond oil, ground nut oil, olive oil and palm oil and mixtures thereofwith polyethylene glycols, in particular polyethylene glycols having anaverage molecular weight of from 200 to 800. Preferred are productsobtained by trans-esterification of 2 molar parts of a natural vegetableoil triglyceride with one molar part of polyethylene glycol (e.g. havingan average molecular weight of from 200 to 800). Various forms oftrans-esterification product of the class defined are known andcommercially available under the trade name LABRAFIL (see Fiedler, loc.cit., 707). Especially useful as components of the compositions of theinvention are the products: LABRAFIL M 1944 CS, a trans-esterificationproduct of kernel oil and polyethylene glycol having an acid no.=ca. 2,a saponification no. ca. 145-175 and an iodine no.=ca. 60-90; andLABRAFIL M 2130 CS, a trans-esterification product of a C₁₂ - to C₁₈ -glyceride and polyethylene glycol having a melting point=ca. 35°-40° C.,an acid no.=<2, a saponification no.=ca. 185-200 and an iodine no.=<3;

3.2.2. Mono-, di- and mono/di-glycerides, especially esterificationproducts of caprylic or capric acid with glycerol. Preferred products ofthis class are e.g. those comprising or consisting mainly or essentiallyof caprylic/capric acid mono- and di-glycerides such as are commerciallyavailable under the trade name IMWITOR (c.f. loc. cit., pp. 645). Aparticularly suitable product of this class for use in the compositionsof the invention is the product IMWITOR 742, which is the esterificationproduct of a mixture of ca. 60 p.p.w. caprylic acid and ca. 40 p.p.w.capric acid with glycerol. IMWITOR 742 is typically a yellowishcrystalline mass, liquid at ca. 26° C.; acid no.=max. 2; iodine no.=max.1; saponification no.=ca. 235-275: % monoglycerides=ca. 40-50%; freeglycerol=max. 2%; m.p.=ca. 24°-26° C.; unsaponifiables=0.3% max.;peroxide no.=max. 1;

3.2.3. Sorbitan fatty acid esters e.g. of the type known andcommercially available under the trade name SPAN, for example includingsorbitan-monolauryl, -monopalmityl, -monostearyl, -tristearyl,-monooleyl and -trioleyl esters-(c.f. Fiedler, loc. cit., pp.1139-1140);

3.2.4. Pentaerythritol fatty acid esters and polyalkylene glycol ethers,for example pentaerythrite- -dioleate, -distearate, -monolaurate,-polyglycol ether and -monostearate as well as pentaerythrite-fatty acidesters (c.f. Fiedler, loc. cit. pp. 923-924);

3.2.5. Monoglycerides, e.g. glycerol monooleate, glycerol monopalmitateand glycerol monostearate, for example as known and commerciallyavailable under the trade names MYVATEX, MYVAPLEX and MYVEROL (c.f.Fiedler, loc. cit., pp. 836), and acetylated, e.g. mono-anddi-acetylated monoglycerides, for example as known and commerciallyavailable under the trade name MYVACET (c.f. Fiedler, loc. cit., pp.835);

3.2.6. Glycerol triacetate or (1,2,3)-triacetin (c.f. Fiedler, loc.cit., pp. 952); and

3.2.7. Sterols and derivatives thereof, for example cholesterols andderivatives thereof, in particular phytosterols, e.g. productscomprising sitosterol, campesterol or stigmasterol, and ethylene oxideadducts thereof, for example soya sterols and derivatives thereof, suchas known under the trade name GENEROL (c.f. Fiedler loc. cit., p.p. 554and 555) in particular the products GENEROL 122, 122 E5, 122 E10, and122 E25.

Compositions as defined under (A) above include systems comprisingeither a single surfactant or mixture of surfactants, e.g. comprising afirst surfactant and one or more co-surfactants. Surfactant andco-surfactant combinations may be selected, e.g. from any of thesurfactant types indicated under (3.1.1.) to (3.2.7.) above.

When the hydrophilic phase comprises a di- or partial-ether as definedunder (1.1) above, in particular TRANSCUTOL or GLYCOFUROL, use of asingle surfactant will generally be sufficient, though co-surfactantsmay be added if desired, e.g. to further improve stabilitycharacteristics. When 1,2-propylene glycol is employed as sole orprinciple hydrophilic phase component, the use of at least twosurfactants, i.e. a surfactant and co-surfactant, will generally berequired. Compositions as defined under (A) comprising 1,2-propyleneglycol as hydrophilic phase thus suitably comprise both a surfactant anda co-surfactant.

Surfactants as defined under (3.1.1.), (3.1.3.), (3.1.7), (3.2.2.) and(3.2.5.) above are of particular interest for use in compositions asdefined under (A). Especially suitable surfactant/co-surfactantcombinations are hydrophilic/lipophilic surfactant combinations, e.g.combinations of surfactants in accordance with (3.1.1.) with surfactantsin accordance with (3.2.5.).

When the surfactant comprises an effective solvent for the cyclosporinactive ingredient, as in the case e.g. of surfactants or mixtures ofsurfactants under (3.1.1.) to (3.2.7.) above, it may be incorporatedinto compositions as defined under (A), not only as surfactant, but inexcess as an additional carrier or co-solvent phase, i.e. as part of thehydrophilic or lipophilic phase.

Compositions in accordance with (A) above may also comprise:

4. A thickening agent.

Suitable thickening agents may be of those known and employed in theart, including, e.g. pharmaceutically acceptable polymeric materials andinorganic thickening agents, for example of the following types:

4.1. Polyacrylate and polyacrylate co-polymer resins, for examplepoly-acrylic acid and poly-acrylic acid/methacrylic acid resins, such asknown and commercially available under the trade name CARBOPOL (c.f.Fiedler, loc. cit., pp. 254-256), in particular the products CARBOPOL934, 940 and 941, and EUDRAGIT (c.f. Fiedler, loc. cit., pp. 486-487),in particular the products EUDRAGIT, E, L, S, RL and RS and, mostespecially, the products EUDRAGIT E, L and S;

4.2. Celluloses and cellulose derivatives including: alkyl celluloses,e.g. methyl-, ethyl- and propyl-celluloses; hydroxyalkyl-celluloses,e.g. hydroxypropyl-celluloses and hydroxypropylalkyl-celluloses such ashydroxypropyl-methyl-celluloses; acylated celluloses, e.g.cellulose-acetates, cellulose-acetatephthallates,cellulose-acetatesuccinates and hydroxypropylmethyl-cellulosephthallates; and salts thereof such as sodium-carboxymethyl-celluloses.Examples of such products suitable for use in accordance with thepresent invention are those known and commercially available, e.g. underthe trade names KLUCEL and METHOCEL (c.f. Fiedler, loc. cit., pp. 688and 790), in particular the products KLUCEL LF, MF, GF and HF andMETHOCEL 100, K 15M, K 100M, E 5M, E 15M and E 100M;

4.3. Polyvinylpyrrolidones, including for examplepoly-N-vinylpyrrolidones and vinylpyrrolidone co-polymers such asvinylpyrrolidone-vinylacetate co-polymers. Examples of such compoundssuitable for use in accordance with the present invention are thoseknown and commercially available, e.g. under the trade name KOLLIDON(or, in the USA, Povidone) (c.f. Fiedler, loc. cit., pp. 694-696), inparticular the products KOLLIDON 30 and 90;

4.4. Polyvinyl resins, e.g. including polyvinylacetates and alcohols, aswell as other polymeric materials including gum traganth, gum arabicum,alginates, e.g. alginic acid, and salts thereof, e.g. sodium alginates;

4.5. Inorganic thickening agents such as atapulgite, bentonite andsilicates including hydrophilic silicon dioxide products, e.g. alkylated(for example methylated) silica gels, in particular colloidal silicondioxide products as known and commercially available under the tradename AEROSIL (c.f. Handbook of Pharmaceutical Excipients, loc. cit.,p.p. 253-256) in particular the products AEROSIL 130, 200, 300, 380, 0,0X 50, TT 600, MOX 80, MOX 170, LK 84 and the methylated AEROSIL R 972.

In the case of compositions in accordance with (A) which are intendedfor oral administration, such thickening agents may be included, e.g. toprovide a sustained release effect. However, where oral administrationis intended, the use of thickening agents as aforesaid will generallynot be required and is generally less preferred. Use of thickeningagents is, on the other hand, indicated, e.g. where topical applicationis foreseen.

Compositions in accordance with (A) above may also include one or morefurther ingredients in particular diluents, anti-oxidants (e.g. ascorbylpalmitate, butyl hydroxy anisole (BHA), butyl hydroxy toluene (BHT) andtocopherols, e.g. α-tocopherol (vitamin E)), flavouring agents and soforth. Use of an anti-oxidant, in particular a tocopherol, isparticularly advantageous.

While it is foreseen, especially where oral administration iscontemplated, that compositions in accordance with the invention asdefined under (A) should comprise end dosage forms for administration assuch, the present invention also provides pharmaceutical compositionscomprising a cyclosporin as active ingredient and which are themselvesmicroemulsions. Thus where oral administration is practiced,microemulsions obtained, e.g. by diluting a "microemulsionpre-concentrate" as defined under (A) with water or other aqueous mediummay be employed as formulations for drinking. Similarly, where topicalapplication is foreseen, compositions comprising a hydrocolloidthickening agent, e.g. as set forth under (4.2.) or (4.4.) above willsuitably also comprise water, thus providing an aqueous microemulsion ingel, paste, cream or like form. Such compositions are also new.Accordingly in a yet further aspect the present invention provides:

B) A pharmaceutical composition which is a microemulsion and comprises acyclosporin as active ingredient.

Compositions as defined under (B) may comprise any of components (1) to(3) as hereinbefore described in relation to compositions as definedunder (A) and water. Compositions (B) are o/w microemulsions. Preferablythey will exhibit stability characteristics as hereinbefore described inrelation to microemulsions obtainable from compositions defined under(A).

In accordance with the present invention it has further been found thatuse of di- or partial-ethers as defined under (1.1.) as carrier media isquite generally advantageous for the preparation of pharmaceuticalcompositions comprising cyclosporins, not only in relation to thepreparation of "microemulsion pre-concentrate" and microemulsionformulations as hereinbefore described. Thus use of such ethers ascomponents of other oral and, in particular, topical delivery systems issurprisingly found of itself to meet difficulties hitherto encounteredin the art as hereinbefore described. Such compositions are also new.Accordingly in a yet further embodiment the present invention alsoprovides:

C) A pharmaceutical composition comprising a cyclosporin as activeingredient, together with a pharmaceutically acceptable C₁₋₅ alkyl ortetrahydrofurfuryl di- or partial-ether of a low molecular weight mono-or poly-oxy-alkane diol.

Preferred ether components for use in compositions as defined under (C)above are as hereinbefore described in relation to (1.1.), the productsTRANSCUTOL and GLYCOFUROL being especially preferred. Compositions inaccordance with (C) suitably contain one or more further ingredients,e.g. surfactants, co-solvents or thickening agents.

In particular, compositions as defined under (C) will suitably alsocomprise a pharmaceutically acceptable hydrophilic surfactant especiallya non-ionic hydrophilic surfactant. Suitable hydrophilic surfactantcomponents are any of those hereinbefore described under (3.1.1.) to(3.1.9.). Compositions as defined under (C) also suitably comprise apharmaceutically acceptable lipophilic surfactant either as a surfactantor as a co-solvent, or a pharmaceutically acceptable co-solvent.Suitable co-solvent/lipophilic surfactant components are any of thosehereinbefore described under (2) and (3.2.1.) to (3.2.7.).

Compositions in accordance with (C) include forms other than as definedunder (A) and (B), for example solutions, suspensions, dispersionsregular emulsions and the like. In particular compositions in accordancewith (C) which additionally comprise a surfactant or both a surfactantand a co-solvent include, for example, emulsion pre-concentrates (i.e.compositions which, on contacting with water, provide regular emulsions--as opposed to microemulsions --of the o/w or w/o type), and regularemulsions of both hydrophilic/lipophilic and lipophilic/hydrophilictype. In the case of formulations, e.g. for drinking or for topicalapplication, they will in particular also include aqueous emulsions ofo/w or w/o type. In general emulsion pre-concentrates giving o/wemulsions and (ii) o/w emulsions as such will be preferred, inparticular where oral administration is contemplated.

Compositions as defined under (C) may further comprise apharmaceutically acceptable thickening agent, suitable thickening agentsbeing any of those hereinbefore described under (4.1.) to (4.5.).

Compositions in accordance with (C) may also comprise further additives,e.g. preserving and floavouring agents etc . . . as hereinbeforedescribed in relation to compositions (A). In particular they willpreferably also include an anti-oxidant, e.g. any of the specificanti-oxidants hereinbefore described in relation to compositions (A). Ofparticular interest in accordance with the present invention are:

D) Compositions as defined under (C) additionally comprising: (5) afatty acid saccharide monoester.

Compositions as defined under (D) will generally comprise thecyclosporin in a carrier medium comprising components (1.1. ), e.g.Glycofurol or Transcutol, and component (5). Commonly, the cyclosporinand component (5) will each be present in compositions in accordancewith (D) in molecular dispersion or solution including, whereappropriate, solid solution. Component (5) will generally act incompositions in accordance with (D) as solubilizor for the cyclosporin.Compositions in accordance with (D) have the particular advantage ofmeeting stability and related difficulties otherwise associated withcomponents (5) resulting from their inherent strongly hygroscopicproperties.

Preferred components (5) for use in compositions in accordance with (D)are water soluble fatty acid saccharide monoesters, e.g. fatty acidmonoesters of saccharides having a solubility in water of at least 3.3%at ambient temperature, e.g. at ca. 20° C., i.e. which are soluble inwater at ambient temperature in an amount of at least 1 g monoester per30 ml water.

The fatty acid moiety of components (5) may comprise saturated orunsaturated fatty acids or mixtures thereof. Particularly suitablecomponents (5) are C₆₋₁₈ -fatty acid saccharide monoesters, inparticular water soluble C₆₋₁₈ -fatty acid saccharide monoesters.Especially suitable components (5) are caproic (C₆), caprylic (C₈),capric (C₁₀), lauric (C₁₂), myristic (C₁₄), palmitic (C₁₆), oleic (C₁₈),ricinoleic (C₁₈) and 12-hydroxystearic (C₁₈) acid saccharide monoesters,especially lauric acid saccharide monoesters.

The saccharide moiety of component (5) may comprise any appropriatesugar residue, e.g. mono-, di- or tri-saccharide residue. Suitably, thesaccharide moiety will comprise a di- or tri-saccharide residue.Preferred components (5) comprise C₆₋₁₄ -fatty acid di-saccharidemonoesters and C₈₋₁₈ -fatty acid tri-saccharide monesters. Especiallysuitable saccharide moieties are saccharose and raffinose residues.

Particularly suitable components (5) are thus: saccharose monocaproate,saccharose monolaurate, saccharose monomyristate, saccharose monooleate,saccharose monoricinoleate, raffinose monocaproate, raffinosemonolaurate, raffinose monomyristate, raffinose monopalmitate andraffinose monooleate. Most preferred components (5) are raffinosemonolaurate and, especially, saccharose monolaurate.

Components (5) will suitably have a hydrophilic-lipophilic balance (HLB)of at least 10.

Components (5) suitably have an ester residue purity of at least 80%,more preferably at least 90%, most preferably at least 95%. Components(5) suitably have a melting point of from about 15° to about 60° C.,more preferably from about 25° to about 50° C.

Compositions in accordance with (D) may also contain furtheringredients, e.g. as hereinbefore described in relation to compositions(C).

In particular, they may include a component capable of modifying therelease characteristics of the composition with respect to thecyclosporin, for example thickening agents, e.g. such as hereinbeforedescribed under (4.1.) to (4.5.).

Compositions in accordance with (D) will in particular also suitablycomprise one or more anti-oxidants, e.g. as hereinbefore specified inrelation to compositions (A).

Compositions in accordance with (D) will also suitably comprise one ormore stabilizors or buffering agents, in particular to preventhydrolysis of component (5) during processing or on storage. Suchstabilizors may include acid stabilizors such as citric acid, aceticacid, tartaric acid or fumaric acid as well as basic stabilizors such aspotassium hydrogen phosphate.

Such stabilizors or buffer agents will appropriately be added in anamount sufficient to achieve or maintain a pH within the range of fromabout 3 to 8, more preferably about 5 to 6, compositions in accordancewith (D) having a pH within the above indicated ranges being generallypreferred.

Compositions in accordance with (D) will in particular also preferablycomprise a polyoxyalkylene-free hydrophilic surfactant, such as setforth under (3.1.6.) or (3.1.7.) above.

Compositions in accordance with the present invention may be employedfor administration in any appropriate manner, e.g. orally, e.g. in unitdosage form, for example in hard or soft gelatin encapsulated form,parenterally or topically e.g. for application to the skin, for examplein the form of a cream, paste, lotion, gel, ointment, poultice,cataplasm, plaster, dermal patch or the like, or for ophthalmicapplication, for example in the form of an eye-drop, -lotion or -gelformulation. Readily flowable forms, for example solutions andmicroemulsions, may also be employed e.g. for intralesional injectionfor the treatment of psoriasis, or may be administered rectally, e.g. asan enema for the treatment of inflammatory bowel disease or Crohn'sdisease. Compositions in accordance with the invention are howeverprimarily intended for oral to topical application, in particularapplication to the skin.

The relative proportion of ingredients in the compositions of theinvention will, of course, vary considerably depending on the particulartype of composition concerned, e.g. whether it is a "microemulsionpre-concentrate", microemulsion, regular emulsion, solution and soforth. The relative proportions will also vary, depending on theparticular function of ingredients in the composition, for example, inthe case of a surfactant component of a "microemulsion pre-concentrate",on whether this is employed as a surfactant only or both a surfactantand a co-solvent. The relative proportions will also vary depending onthe particular ingredients employed and the desired physicalcharacteristics of the product composition, e.g. in the case of acomposition for topical use, whether this is to be a free flowing liquidor a paste. Determination of workable proportions in any particularinstance will generally be within the capability of the man skilled onthe art. All indicated proportions and relative weight ranges describedbelow are accordingly to be understood as being indicative of preferredor individually inventive teachings only and not as not limiting theinvention in its broadest aspect.

The amount of cyclosporin in compositions of the invention will ofcourse vary, e.g. depending on the intended route of administration andto what extent other components, in particular components (2) to (5) ashereinbefore described, are present. In general however the cyclosporinwill be present in an amount within the range of from 0.05 especiallyabout 0.1 to about 35% by weight based on the total weight of thecomposition.

Components (1) will suitably be present in the compositions of theinvention in an amount of from about 0.5 to about 90% by weight based onthe total weight of the composition. In the case of compositions inaccordance with the invention comprising a component (1.1.) (e.g.GLYCOFUROL or TRANSCUTOL), (1.1.) will generally be present in an amountof from about 1 to about 90% by weight, more commonly from about 5 or 10to about 70% by weight based on the total weight of the composition. Inthe case of compositions in accordance with (A) or (B) above comprisinga component (1.2.), (1.2.) will generally be present in an amount offrom about 2 to about 50% by weight based on the total weight of thecomposition. In the case of compositions in accordance with theinvention comprising a component (2) or (3), these will each begenerally present in an amount of from about 0.5 to about 90% by weightbased on the total weight of the composition. In an especially preferredaspect the present invention relates to:

E) Compositions as defined under (A) or (C) above for oraladministration, e.g. in a form suitable or convenient for oraladministration. For compositions as defined under (A) to (C) intendedfor non-topical administration and, in particular, for oral dosage forms(E):

a) The cyclosporin will generally be present in an amount of from about1 or 2 to about 30%, suitably from about 4 to about 25% by weight basedon the total weight of the composition. More suitably the cyclosporinwill be present in an amount of from about 5 to about 25, especially toabout 20%, e.g. from about 5 to 15% by weight based on the total weightof the composition;

b) Component (1.1) when present will generally be present in an amountof from about 15 to about 85, suitably from about 20 to about 80, moresuitably from about 25 to about 70, e.g. from about 30 to about 50 or60% by weight based on the total weight of the composition;

c) Cyclosporin and component (1.1.) when present will generally bepresent in a ratio of about 1:0.75 to 20, suitably about 1:1 to 15, moresuitably about 1:1 to 5, e.g. about 1:1 or 1:1.5 to 4 p.p.w.(Cyclosporin: (1.1.));

d) Component (1.2.) when present will generally be present in an amountof from about 3 to about 45, suitably about 5 to about 30% by weightbased on the total weight of the composition;

e) Cyclosporin and component (1.2.) when present will generally bepresent in a ratio of about 1:0.1 to 20, suitably about 1:0.2 to 10p.p.w.. More suitably they will be present in a ratio of about 1:0.3 to6, e.g. about 1:0.5 to 3 p.p.w. (Cyclosporin: (1.1)).

f) Component (2) when present will generally be present in an amount upto about 45%, suitably up to about 40% by weight based on the totalweight of the composition. More suitably component (2) will be presentin an amount of from about 2 to about 45, yet more suitably from about 3to about 35, most suitably from about 5 or 10 to about 30% by weightbased on the total weight of the composition.

g) Components (2) and (1.1) when present will generally be present in aratio of about 1:0.5 to 40, suitably about 1:0.5 to 20, more suitablyabout 1:0.75 to 10, e.g. about 1:0.75 to 4 p.p.w. ((2):(1)).

h) Components (2) and (1.2) when present will suitably be present in aratio of about 1:0.075 to 22, suitably about 1:0.1 to 15, most suitablyabout 1:0.15 to 6 p.p.w., e.g. about 1:0.5 to 3 p.p.w. ((2):(1.2)).

i) Components (3) when present (including both components of type (3.1.)and (3.2.)), will generally be present in an amount of up to about 90,e.g. from about 20 to about 90% by weight based on the total weight ofthe composition. More suitably components (3) will be present in anamount of from about 20 or 25 to about 80 or 90% by weight based on thetotal weight of the composition, e.g. from about 25 to about 55% when acomponent (1.1) is employed or from about 40 to 75% when a component(1.2) is employed.

j) Cyclosporin and component (3) (including both components of type(3.1.) and (3.2.)) when present will generally be present in a ratio ofabout 1:0.5 to 20, more suitably to 12 p.p.w.. Appropriately they willbe present in a ratio of about 1:1 to 10 p.p.w., e.g. about 1:1 to 5p.p.w. when a component (1.1) is present or about 1:3 to 8 p.p.w. when acomponent (1.2) is present. (Cyclosporin: (3)).

For compositions as defined under (A) and (B) ["microemulsionpre-concentrates" and microemulsions] the relative proportions ofingredients comprising (1) the hydrophilic phase, (2) the lipophilicphase and (3) the surfactant will vary with the concentration ofcyclosporin present. They will also vary in relative proportion to eachother.

Compositions according to (A) may thus be defined as comprising acyclosporin together with (1) a hydrophilic phase (e.g. as defined under(1.1) or (1.2) above), (2) a lipophilic phase (e.g. as defined under(2.1) or (2.2) above) and a surfactant (e.g. as defined under (3.1) or(3.2) above), the relative proportions of cyclosporin: (1):(2):(3) beingsuch that on contact with water, e.g. as hereinbefore indicated inrelative proportions of 1:1 p.p.w. [cyclosporin+(1)+(2)+(3)):H₂ O] ormore, a microemulsion (e.g. of o/w type] is obtainable.

Similarly compositions according to (B) may be defined as comprising acyclosporin together with components (1), (2) and (3) as aforesaid andwater in relative proportions, e.g. as hereinbefore indicated, requiredto provide a microemulsion (e.g. of o/w type).

Compositions in accordance with (A) and (B) preferably comprise fromabout 2 to about 30, more preferably from about 5 to about 20, mostpreferably from about 10 to about 15% by weight of cyclosporin based onthe total weight of cyclosporin plus components (1)+(2)+(3).

When (1) of compositions (A) or (B) is as defined under (1.1) above,e.g. comprises TRANSCUTOL OR GLYCOFUROL, components (1.1), (2) and (3)will preferably be present in amounts of from about 15 to about 85%,more preferably from about 25 to about 65% of (1.1), from about 2 toabout 40, more preferably from about 3 to about 35 most preferably fromabout 3 to about 30% of (2) and from about 15 to about 85, morepreferably from about 25 to about 55 or 60% of (3), all % ages being byweight based on the total of (1.1)+(2)+(3). Use of GLYCOFUROL is ofparticular interest.

When (1) of compositions (A) or (B) is 1,2-propylene glycol ((1.2)above), components (1.2.), (2) and (3) will suitably be present inamounts of from about 3 to about 35%, more preferably from about 3 toabout 25% of (1.2), from about 2 to about 35%, more preferably fromabout 3 to about 30% of (2) and from about 45 to about 90%, morepreferably from about 50 to about 90%, e.g. from about 55 to about 80%of (3), all % ages being by weight based on the total of (1.2)+(2)+(3).As previously indicated, when (1) is 1,2-propylene glycol component (3)will generally comprise both a surfactant and a co-surfactant. When aco-surfactant is employed, surfactant and co-surfactant will suitably bepresent in a ratio of up to about 50:1, preferably up to 20:1, morepreferably up to 15:1, e.g. from 2 to 15:1 p.p.w. (surfactant:co-surfactant).

FIG. 1 attached, represents a three-way plot for relative concentrationsof components (1.1) (e.g. GLYCOFUROL); (2) (e.g. MIGLYOL 801), and (3)(e.g. CREMOPHORE RH40) in compositions according to (A) and comprisingca. 10% cyclosporin (e.g. Ciclosporin) by weight. Relative concentrationof component (1.1) increases from 0% along the left hand margin of theplot to 100% at the lower right corner, as indicated by the arrow "1.1".Concentration of component (2) increases from 0% at the right handmargin of the plot to 100% at the lower left corner, as indicated by thearrow "2". Thus a composition comprising 50% of (1.1) and 50% of (2)only, is designated at the mid-point of the base-line of the plot.Relative concentration of component (3) increases from 0% at thebase-line of the plot to 100% at the apex, as indicated by the arrow"3". Lines within the plot represent increments of 10%, from 0% at eachmargin to 100% at the apex opposite.

For compositions as defined under (A) and (B) the relative proportion ofcomponents (1.1), (2) and (3) will suitably lie within the area Adefined by the line a of FIG. 1. More suitably the relative proportionof components (1.1), (2) and (3) will lie within the area B defined bythe line b of FIG. 1, microemulsions based on these proportions beingfound to have greatest stability, e.g. of >24 hrs./an average particlesize of less than 1,000 Å. Compositions in accordance with the inventioncomprising the components (1.1), (2) and (3) in relative proportion asdefined above with reference to FIG. 1 accordingly represent especiallypreferred embodiments.

FIG. 2 attached, represents a three-way plot for relative concentrationsof components (1.2), (2) e.g. MIGLYOL 812 and (3) in compositionsaccording to (A) and comprising ca. 10% cyclosporin (e.g. Ciclosporin)by weight. In this case (3) comprises an appropriatesurfactant/co-surfactant mixture, e.g. in a ratio of 11:1 p.p.w., forexample comprising 11 p.p.w. CREMOPHOR RH40 and 1 p.p.w.Glycerinmonooleate. Relative amounts of components (1.2), (2) and (3)are indicated, as for FIG. 1, by arrows "1.2", "2" and "3" respectively.

For compositions as defined under (A) and (B) the relative proportionsof components (1.2), (2) and (3) will suitably lie within the area Xdefined by the line x of FIG. 2. More suitably the relative proportionof components (1.2), (2) and (3) will lie within the area Y defined byline y of FIG. 2. Most suitably the relative proportion of components(1.2), (2) and (3) will lie within the area Z of FIG. 2 defined by linez, microemulsions based on proportions within the areas Y and Z havingan average particle size of the order of 1,100 Å and <200 Å respectivelyand a stability, e.g. of >24 hrs.

Compositions in accordance with (E) above may additionally include athickening agent, though, as previously indicated, this will generallybe less preferred. Suitable thickening agents include any of thosehereinbefore described under (4) above. The amount of thickening agentpresent may vary e.g. depending on the required consistency of the endproduct, e.g. whether it is to be in a thickened flowable form, forexample for filling into a capsule or the like, or sufficientlyresilient to be mouldable or formable, e.g. for use in the manufactureof tablets or the like. The amount will of course also depend on thenature of the thickening agent chosen. In general components (4), whenpresent will be present in an amount of up to about 25% by weight basedon the total weight of the composition, more suitably in an amount of upto about 15 or 20% by weight, e.g. in an amount of from 0.5 or 5 up to15 or 20% by weight based on the total weight of the composition.

Compositions in accordance with (E) may also include further additivesor ingredients, e.g. as hereinbefore described with reference tocompositions (A) and (C). In particular they may comprise antioxidants,e.g. in an amount of up to about 0.5 or 1% by weight based on the totalweight of the composition, and sweetening or flavouring agents, e.g. inan amount of up to about 2.5 or 5% by weight based on the total weightof the composition.

Compositions (E) in accordance with definition (A) have been found toexhibit especially advantageous properties when administered orally,e.g. in terms of both the consistancy and high level of bioavailabilityachieved. In particular, and in contrast with other galenic systems,e.g. as known from the art, it has been found that such compositions arecompatible with tenside materials, e.g. bile salts, present in thegastro-intestinal tract. That is, they are fully dispersible in aqueoussystems comprising such natural tensides and are thus capable ofproviding microemulsion systems in situ which are stable and do notexhibit precipitation or other disruption of fine particulate structure.Function of such systems on oral administration remains independent ofand/or unimpaired by the relative presence or absence of bile salts atany particular time or for any given individual. Such compositionsaccordingly represent an especially preferred embodiment of theinvention.

Compositions in accordance with (E) above will preferably be compoundedin unit dosage form, e.g. by filling into orally administerable capsuleshells, e.g. soft or hard gelatine capsule shells or by tabletting orother moulding process. Where compositions (E) are in unit dosage form,each unit dosage will suitably contain between about 5 or 10 and about200 mg cyclosporin, more suitably between about 15 or 25 and about 150mg, e.g. 25, 50 or 100 mg cyclosporin. Thus unit dosage forms inaccordance with the invention, suitable for administration 1×, 2× or 3×up to 5× daily (e.g. depending on the particular purpose of therapy, thephase of therapy etc . . . ) will appropriately comprise e.g. about 50mg or about 100 mg cyclosporin per unit dosage.

Compositions in accordance with (B) above for oral administration may beprepared, by addition of compositions as described in relation to (A) or(E) above to water or any other aqueous system, e.g. in relativeproportions (composition:H₂ O) as hereinbefore indicated, for example asweetened or flavoured preparation for drinking. Such compositions maythus comprise any system as hereinabove defined or described in relationto compositions (A) or (E), plus sufficient water to form amicroemulsion.

Compositions as defined under (D) above are, in particular, intended fororal administration, though use in form suitable, e.g. for topical,including dermal and topical ophthalmic, parenteral or rectaladministration, as well as for intralesional injection, is alsoembraced.

In the case of compositions as defined under (D) the cyclosporin andrequired component (1.1) may be present in a ratio of about 1:0.5 to200, preferably about 1:0.5 to 100, more preferably about 1:0.5 to 50p.p.w.. Yet more suitably they will be present in a ratio of about 1:1to 10, more preferably 1:1 to 5, most preferably about 1:1.5 to 2.5,e.g. about 1:1.6 or 1:2 p.p.w. (Cyclosporin: (1.1)). Cyclosporin andrequired component (5) will suitably present in a ratio of about 1:3 to200, preferably about 1:3 to 100, more preferably about 1:3 to 50p.p.w.. Yet more suitably they will be present in a ratio of about 1:5to 20, preferably about 1:5 to to 10, most preferably about 1:6.0 to6.5, e.g. about 1:6.25 p.p.w. (Cyclosporin:(1.1)).

Suitably compositions in accordance with (D) will be made up in unitdosage form, whether for oral administration or otherwise.

The amount of cyclosporin present in such unit dosage forms will ofcourse vary depending on e.g. the condition to be treated, the intendedmode of administration and the effect desired. In general however, unitdosage forms in accordance with (D) will suitably comprise from about 2to about 200 mg cyclosporin, per unit dosage.

Suitable dosage forms for oral administration include e.g. liquids,granulates and the like. Preferred dosage forms are however unit dosageforms, for example tabletted or encapsulated forms, in particular hardor soft gelatin encapsulated forms.

Unit dosage forms for oral administration in accordance with (D) willsuitably comprise from about 5 or 10 to about 200 mg, more suitably fromabout 15 or 20 to about 100 mg, e.g. 25, 50 or 100 mg cyclosporin perunit dosage.

Compositions (D) have the further advantage that they are able toprovide the basis for compositions exhibiting modified releasecharacteristics, for example delayed release of cyclosporin or releaseof cyclosporin over prolonged periods of time, e.g. following oraladministration. Such compositions additionally comprise a componentcapable of modifying the release characteristics of the composition withrespect to the cyclosporin. Such components include, for example, (4), athickening agent, e.g. in accordance with any of (4.1) to (4.5) above.

When compositions (D) comprise a component (4), this is suitably presentin an amount of from about 0.5 to 50%, more preferably from about 1 to20%, most preferably from about 2 to 10% by weight based on the totalweight of Cyclosporin plus (1.1)+(4)+(5).

As previously indicated, compositions in accordance with (D) willadvantageously include one or more stabilizors or buffering agents orpolyoxyalkylene-free surfactants. Such stabilizors and/or bufferingagents will suitably be present in an amount of up to 5% by weight or,when citric or acetic acid are employed, up to 10% by weight based onthe weight of cyclosporin plus (1.1)+(5). When a surfactant as aforesaidis present, this is suitably present in an amount of from about 5 toabout 50, more preferably from about 10 to about 25% by weight based onthe weight of component (5).

Compositions in accordance with (D) will also suitably comprise furtheradditives in particular flavouring agents or, in particular,anti-oxidants. Suitable anti-oxidants and quantities employed are ashereinbefore described in relation to compositions (E).

Compositions in accordance with (D) will also preferably be free orsubstantially free of lower alkanols, in particular ethanol, e.g.comprise less than 5%, more preferably less then 2%, e.g. from 0 to 1%,lower alkanolic components based on the total weight of the composition.

Compositions as defined under (A) to (C) are also of particular interestfor topical administration. Accordingly in a yet further aspect thepresent invention provides:

F) Compositions as defined under any one of (A) to (C) above fortopical, especially for dermal application, i.e. in a form suitable orconvenient for topical application.

Where topical administration is contemplated, the cyclosporin willsuitably be present in an amount of from about 0.05, more preferablyfrom about 0.1, to about 15% by weight based on the total weight of thecomposition. More preferably the cyclosporin will be present in anamount of from about 0.1 to about 10% by weight.

In the case of compositions (F) which are compositions in accordancewith (A) or (B), the relative proportion of components (1), (2) and (3)will be as hereinbefore described for such compositions, e.g. withreference to FIGS. I and II.

Compositions (F) in accordance with (C) the other hand may take anysuitable form, e.g. comprise solutions, suspensions, dispersions andregular emulsions. Component (1.1) may suitably be present in suchcompositions in an amount of from about 1 to about 70%, preferably fromabout 5 to about 50%, more preferably from about 7 to about 25% byweight based on the total weight of the composition.

Compositions (F) will suitably comprise one or more carriers or diluentsand/or other ingredients providing a carrier system, e.g. thickeningagents, emulsifying agents, preserving agents, moisturising agents,colourants and so forth.

Compositions (F) may be in any form suitable for topical application,e.g. application to the skin surface, for example flowable, e.g. liquidor semi-liquid form, in the form of a powder or in the form of atopically applicable spray. Examples of suitable flowable forms includee.g. gels, including oil-in-water and water-in-oil emulsions ormicroemulsions, creams, pastes and ointments and the like as well aslotions, and tinctures, etc.. Such compositions also include, e.g.cataplasms and poultices as well as transdermal patch systems.

Selection of excipients for the preparation of such formulations will,of course, be determined by the type of formulation desired as well asthe particular condition to be treated, the status of the condition,area to be treated, skin condition and effect desired. Thus chronicpsoriatic plaques will more suitably be treated with hydrophobic, e.g.fat-based compositions, for example compositions in accordance with theinvention comprising a petrolatum based ointment or cream as carriermedium. In contrast, compositions for use in the treatment of diseaseconditions involving acute phase inflammatory processes will moreappropriately be treated with more hydrophilic compositions, e.g.compositions in accordance with the invention in the form of anoil-in-water emulsion or gel. Although, compositions (F) may comprise,e.g. lower alkanols, for example ethanol, for example as diluent ordiluent component, use of these will preferably be avoided, e.g. wherecompromised skin is to be treated, as in the case of psoriasis.Preferred compositions (F) are thus free or substantially alkanol free,e.g. contain less than 5%, more preferably less than 2%, e.g. from about0 to 1% by weight alkanolic components, in particular of ethanol.

Especially preferred compositions (F) are compositions in accordancewith (A), (B) or (C) additionally comprising: (6) a (further)pharmaceutically acceptable diluent or carrier which is non-misciblewith component (1.1.). Compositions as aforesaid will preferably takethe form of a water-free or substantially water-free emulsion, i.e.comprise less than 10%, preferably less than 5%, most preferably lessthan 1% water. Such emulsions include both emulsions comprisingcomponent (1.1.) in (6), and emulsions comprising (6) in (1.1.).Preferably they will comprise an emulsion of (1.1.) in (6).

Suitable components (6) include, for example:

6.1. Solid hydrocarbons, for example petroleum jellies, e.g. whitepetrolatum or VASELINE, ceresin and solid paraffins, as well as waxesincluding animal, vegetable and synthetic waxes such as, for example,spermaceti, carnauba and bees wax;

6.2. Liquid hydrocarbons, e.g. liquid paraffins and fatty acid esterssuch as isopropylmyristate and cetyl palmitate;

6.3. Non-volatile silicones including silicone oils and pastes, andsilicone-polyalkyleneoxide co-polylymers (c.f. Fiedler, loc. cit., pp.1109 and 1110) for example such as known and commercially availableunder the trade name PIROETHICON

Components (6) will suitably be present in compositions (F) in an amountof up to about 80%, e.g. from about 5 to about 70%, preferably fromabout 25 to about 60% by weight based on the total weight of thecomposition.

By use of individual ingredients (6) or mixtures thereof, emulsions maybe obtained in liquid or semi-solid form depending on, e.g., desiredrequirements for topical application.

Compositions (F) will suitably also comprise a surfactant. Suitablesurfactants include, in particular, lipophilic surfactants, includingany of those listed under (3.2.1.) to (3.2.7.) above, especiallysurfactants having an HLB of ca. 5-7. Examples of surfactants ofparticular utility in relation to compositions (F) include for example,surfactants as described under (3.1.2.), and (3.2.3.) above as well asglycerol monstearate, propyleneglycol monostearate, diethyleneglycolmonostearate and glycerol ricinoleate.

Surfactants as aforesaid will suitably be present in compositions (F) inan amount of up to about 60%, e.g. from about 2 to about 50%, preferablyfrom about 10 to about 40% by weight based on the total weight of thecomposition.

Compositions (F) may further comprise one or more consistency promotingagents, for example microcrystalline waxes, vegetable oils such as oliveoils, corn oils and kernel oils, and vegetable oil derivatives includinghydrogenated vegetable oils and vegetable oil partial-glycerides, e.g.in an amount of from about 0.1 to about 10%, preferably from about 1 toabout 5% weight based on the total weight of the composition.

Compositions (F) will also suitably comprise:

an anti-oxidant, e.g. any of the antioxidants hereinbefore described inrelation to compositions (A), for example in an amount of from about0.01 to about 0.5% by weight based on the total weight of thecomposition;

an anti-bacterial agent, e.g. benzyl alcohol, methyl- or propyl-paraben,benzalkonium chloride, benzoic acid, sorbic acid or chlorobutanol, forexample in an amount of from about 0.05 to about 2% by weight based onthe total weight of the composition;

a stabilizor such as microcrystalline starch, sodium EDTA or magnesiumsulfate, e.g. in an amount of from about 0.1 to about 10% by weightbased on the total weight of the composition; and/or

a skin penetration enhancer, for example a C₁₂₋₂₄ mono- orpoly-unsaturated fatty acid or alcohol (e.g. vaccenic, cis-vaccenic,linoleic, linolenic, elaidic oleic, petroselinic, erucic or nervonicacid or any of their corresponding alcohols, especially oleic acid oroleyl alcohol), or 1-dodecylazacycloheptan-2-one also known as Azone(c.f. Fiedler, loc. cit., p. 190), e.g. in an amount of from about 1 toabout 20, suitably from about 3 to about 15% by weight based on thetotal weight of the composition.

In addition to the foregoing the present invention also provides aprocess for the production of a pharmaceutical composition ashereinbefore defined, e.g. as hereinbefore defined under anyone of (A)to (F) above, which process comprises bringing the individual componentsthereof into intimate admixture and, when required compounding theobtained composition in unit dosage form, for example filling saidcomposition into gelatin, e.g. soft or hard gelatin, capsules.

In a more particular embodiment the invention provides a process for thepreparation of a composition as defined under any one of (A) to (D)above, which process comprises bringing a cyclosporin, e.g. Ciclosporin,into inimite admixture with a component (1.1) as hereinbefore defined toobtain a composition as defined under (C) and, optionally, a component(5) as hereinbefore defined to obtain a composition as defined under(D), or with a component (1.2) as hereinbefore defined, wherebyoptionally when a component (1.1) is employed, or necessarily when acomponent (1.2) is employed, said aforesaid ingredients are furthercombined with a component (2) and a component (3) as hereinbeforedefined, the relative proportions of component (1.1) or (1.2), and (3)being chosen such that a composition as defined under (A) is obtainedand further, when required, contacting said obtained composition (A)with water, so as to obtain a composition as defined under (B) and whenrequired, compounding an obtained composition (A), (C) or (D) in unitdosage form, e.g. soft or hard gelatin capsule form.

In a specific embodiment the present invention provides a process forproducing a composition as defined under (A) above, which processcomprises intimately admixing a cyclosporin, e.g. Ciclosporin, with acomponent (1.1) or (1.2) as hereinbefore defined, and a component (2)and a component (3) as hereinbefore defined, the relative proportion ofthe components (1.1) or (1.2), (2) and (3) being selected relative tothe quantity of cyclosporin employed such that a "microemulsionpre-concentrate", e.g. composition capable on addition to water, e.g. ina ratio of at least 1:1 p.p.w. (composition:H₂ O) of providing a systemcomprising a dispersed or particle phase of which the individualparticles have a size of less than 2,000 Å, preferably of from about 100to about 1,000 Å is obtained.

The preferred cyclosporin in relation to the composition of theinvention is Ciclosporin. A further preferred cyclosporin to which theteachings of the present invention are applicable is [Nva]²-Ciclosporin, also known as cyclosporin G.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 represents a three-way plot for relative concentrations ofcomponents (1.1) (e.g. GLYCOFUROL), (2) (e.g. MIGLYOL 812), and (3)(e.g. CREMOPHORE RH40) in compositions according to (A) and comprisingca. 10% cyclosporin by weight. Relative concentration of component (1.1)increases from 0% along the left hand margin of the plot 100% at thelower right corner, as indicated by the arrow "1.1". Concentration ofcomponent (2) increases from 0% at the right hand margin of the plot to100% at the lower left corner, as indicated by the arrow "2". Relativeconcentration of component (3) increases from 0% at the base-line of theplot to 100% at the apex, as indicated by the arrow "3". Lines withinthe plot represent increments of 10%, from 0% at each margin to 100% atthe apex opposite. The relative proportion of components (1.1), (2) and(3) will suitably lie within the area A defined by the line a of FIG. 1.More suitably, the relative proportion of components (1.1), (2), and (3)will lie within the area B defined by the line b of FIG. 1.

FIG. 2 represents a three-way plot for relative concentrations ofcomponents (1.2), (2) e.g. MIGLYOL 812 and (3) in compositions accordingto (A) and comprising ca. 10% cyclosporin by weight. In this case (3)comprises an appropriate surfactant/co-surfactant mixture, e.g. in aratio of 11:1 parts by weight (pbw), for example comprising 11 pbwCREMOPHOR RH40 and 1 pbw Glycerinmonooleate. Relative amounts ofcomponents (1.2), (2) and (3) are indicated, as for FIG. 1, by arrows"1.2", "2" and "3" respectively. The relative proportions of components(1.2), (2) and (3) will suitably lie within the area X defined by line xof FIG. 2; more suitably within the area Y defined by line y of FIG. 2;and most suitably within the area Z of FIG. 2 defined by line z.

FIGS. 3 and 4 provide superimposed graphical representations from atrial of whole blood Ciclosporin concentrations recorded for 12 trialparticipants following single oral administrations of COMPOSITION I(FIG. 3) and COMPOSITION X (FIG. 4), each in an amount providing aCiclosporin dosage of 150 mg, as determined by specific monoclonal RIA.Blood concentration (in ng/ml) is recorded vertically, and time (inhrs.) horizontally.

The following examples are illustrative of compositions in accordancewith the present invention. Examples 1,2,4,5 and 7 illustrate thepreparation of compositions in oral unit dosage form, suitable for use,e.g. in the prevention of transplant rejection or for the treatment ofautoimmune disease, e.g. any of the autoimmune diseases or conditionshereinbefore described, on administration of from 1 to 5 unitdosages/day. Examples 3 and 6 illustrate the preparation of compositionsfor topical application, suitable for treatment, e.g. of atopic orcontact dermatitis, psoriasis or hair loss, on application at thedesired site of therapy, e.g. dermatitidic reaction or psoriatic lesionor to the scalp, at regular intervals, e.g. once, twice or three timesper day.

The examples are described with particular reference to Ciclosporin.However, equivalent compositions may be obtained employing any otherappropriate cyclosporin. In particular equivalent compositions may inall cases be obtained on replacement of Ciclosporin with [Nva]²-Ciclosporin in the same amount as indicated for Ciclosporin.

EXAMPLE 1 Preparation of Oral Dosage Forms: "MicroemulsionPre-Concentrate" Type

    ______________________________________                                                                     QUANTITY                                         1.1. COMPONENT               (mg/capsule)                                     ______________________________________                                                 Cyclosporin (e.g. Ciclosporin)                                                                    50.0                                             (1.1)    Glycofurol 75       180.0                                            (2.1)    Miglyol 812         90.0                                             (3.1.1)  Cremophor RH 40     180.0                                                     TOTAL               500.0                                            ______________________________________                                    

The cyclosporin is dissolved in (1.1) with stirring at room temperatureand (2.1) and (3.1.1) are added to the obtained solution, again withstirring. The obtained mixture is filled into a size 1 hard gelatincapsule and sealed using Quali-Seal technique.

The following compositions may be prepared analogously for filling intosize 1 or 2 hard gelatin capsules:

    ______________________________________                                                                 QUANTITY                                             COMPONENT                (mg/capsule)                                         ______________________________________                                        1.2.         Cyclosporin (e.g. Ciclosporin)                                                                    50.0                                              (1.1)   Glycofurol 75       180.0                                             (2.1)   Miglyol 812         78.0                                              (3.1.1) Cremophor RH 40     192.0                                                     TOTAL               500.0                                        1.3.         Cyclosporin (e.g. Ciclosporin)                                                                    50.0                                              (1.1)   Glycofurol 75       200.0                                             (2.1)   Miglyol 812         60.0                                              (3.1.1) Nikkol HCO-40       120.0                                                     Ethanol*            19.0                                                      Ascorbylpalmitate** 1.0                                                       TOTAL               450.0                                        1.4.         Cyclosporin (e.g. Ciclosporin)                                                                    50.0                                              (1)     Glycofurol 75       100.0                                             (2.1)   Miglyol 812         75.0                                              (3.1.7) Lecithin            75.0                                                      TOTAL               300.0                                        1.5.         Cyclosporin (e.g. Ciclosporin)                                                                    100.0                                             (1.1)   Glycofurol 75       260.0                                             (1.2)   Propyleneglycol     50.0                                              (2.1)   Myritol 318         100.0                                             (3.1.1) Cremophor RH 40     340.0                                                     BHA**               5.0                                                       TOTAL               855.0                                        1.6.         Cyclosporin (e.g. Ciclosporin)                                                                    50.0                                              (1.2)   1,2-Propyleneglycol 68.0                                              (2.1)   Miglyol 812         68.0                                              (3.1.1) Cremophor RH 40     250.0                                             (3.2.5) Glycerol monooleate***                                                                            24.0                                                      TOTAL               460.0                                        1.7.         Cyclosporin (e.g. Ciclosporin)                                                                    50.0                                              (1.2)   1,2-Propylenglycol  68.0                                              (2.1)   Miglyol 812         24.0                                              (3.1.1) Cremophor RH 40     250.0                                             (3.2.5) Glycerol monooleate***                                                                            68.0                                                      TOTAL               460.0                                        1.8.         Cyclosporin (e.g. Ciclosporin)                                                                    100.0                                             (1.2)   1,2-Propyleneglycol 75.0                                              (2.1)   Miglyol 812         25.0                                              (3.1.1) Cremophor RH 40     150.0                                             (3.2.5) Glycerol monooleate***                                                                            150.0                                                     TOTAL               500.0                                        1.9.         Cyclosporin (e.g. Ciclosporin)                                                                    50.0                                              (1.2)   1,2-Propyleneglycol 200.0                                             (2.1)   Miglyol 812         50.0                                              (3.1.1) Cremophor RH 40     150.0                                             (3.2.7) Generol 122 E16***  50.0                                                      TOTAL               500.0                                        1.10.        Cyclosporin (e.g. Ciclosporin)                                                                    50.0                                              (1.2)   1,2-Propyleneglycol 75.0                                              (2.1)   Miglyol 812         75.0                                              (3.1.1) Cremophor RH 40     250.0                                             (3.2.7) Generol 122 E25***  50.0                                                      TOTAL               500.0                                        ______________________________________                                         *Co-solvent (hydrophilic phase)                                               **Antioxidant                                                                 ***Cosurfactant                                                          

Compositions 1.1, 1.2, 1.6 and 1.7 are especially preferred. Equivalentcompositions to 1.1 to 1.5 can in all cases be prepared replacing theGlycofurol component with Transcutol in the same or equivalent amount.

Equivalent compositions to 1.1 to 1.5 may be prepared but replacing the50 mg amount of cyclosporin with 15, 20 or 100 mg cyclosporin (e.g.Ciclosporin) the quantities of the remaining components for eachcomposition remaining as indicated.

EXAMPLE 2 Preparation of Oral Dosage Forms: Thickened "MicroemulsionPre-Concentrate" Type

    ______________________________________                                                                     QUANTITY                                         2.1. COMPONENT               (mg/capsule)                                     ______________________________________                                                 Cyclosporin (e.g. Ciclosporin)                                                                    50.0                                             (1.1)    Glycoiurol 75       180.0                                            (2.1)    Miglyol 812         90.0                                             (3.1.1)  Cremophor RH 40     180.0                                            (4.2)    Methocel K100       100.0                                                     TOTAL               600.0                                            ______________________________________                                    

Ciclosporin and (1.1) to (3.1.1) are combined as in example 1 and theobtained mixture mixed homogeneously with (4.2). The product is filledinto size 2 hard gelatin capsules.

The following composition may be obtained analogously:

    ______________________________________                                                                 QUANTITY                                             COMPONENT                (mg/capsule)                                         ______________________________________                                        2.2.         Cyclosporin (e.g. Ciclosporin                                                                     50.0                                              (1.1)   Glycofurol 75       180.0                                             (2.1)   Miglyol 812         90.0                                              (3.1.1) Cremophor RH 40     180.0                                             (4.6)   Aerosil 200         9.0                                               (4.2)   Methocel K100       100.0                                                     TOTAL               609.0                                        2.3.         Cyclosporin (e.g. Ciclosporin)                                                                    100.0                                             (1.1)   Glycofurol          210.0                                             (2.1)   Myritol 318         90.0                                              (3.1.1) Nikkol HCO-60       170.0                                             (4.2)   Klucel EF           30.0                                                      TOTAL               600.0                                        ______________________________________                                    

Equivalent compositions to 2.1 to 2.3 can be prepared replacing theGlycofurol component with Transcutol in the same or equivalent amount.

EXAMPLE 3 Preparation of Topically Applicable Form: "MicroemulsionPre-Concentrate" Type

    ______________________________________                                        COMPONENT             % BY WEIGHT                                             ______________________________________                                               Cyclosporin (e.g. Ciclosporin)                                                                   0.1                                                 (1.1)  Glycofurol         50.0                                                (2.1)  Miglyol 812        16.6                                                (3.1.1)                                                                              Cremophor RH 40    33.3                                                ______________________________________                                    

The above composition is prepared analogously to example 1. Anequivalent composition is obtained on replacement of the Glycofurolcomponent with Transcutol. The composition may be made the basis of acream, gel or the like by combination with further additives, e.g.hydrocolloid thickening agents, paraffins etc. . . as hereinbeforedescribed.

EXAMPLE 4 Preparation of Oral Dosage Forms: Regular EmulsionPre-concentrate Type

    ______________________________________                                                                    QUANTITY                                          4.1. COMPONENT              (mg/capsule)                                      ______________________________________                                                 Cyclosporin (e.g. Ciclosporin)                                                                   100.0                                             (1.1)    Transcutol         154.0                                             (3.1.1)  Cremophor RH 40    146.0                                             (3.2.1)  Labrafil M 1944 CS 50.0                                                       TOTAL              450.0                                             ______________________________________                                    

Cyclosporin is dissolved in (1.1) with stirring at room temperature and(3.1.1) and (3.2.1) added to the obtained solution, again with stirring.The obtained mixture is filled into size 1 hard gelatin capsules andsealed employing Quali-Seal technique.

The following compositions may be prepared analogously for filling intosize 1 or 2 hard gelatin capsules as appropriate.

    ______________________________________                                                                 QUANTITY                                             COMPONENT                (mg/capsule)                                         ______________________________________                                        4.2.          Cyclosporin (e.g. Ciclosporin)                                                                   50.0                                              (1.1)    Transcutol         80.0                                              (3.1.1)  Cremophor RH 40    75.0                                              (3.2.1)  Labrafil M 2130 CS 25.0                                                       TOTAL              230.0                                        4.3.          Cyclosporin (e.g. Ciclosporin)                                                                   100.0                                             (1.1)    Glycofurol 75      150.0                                             (3.1.1)  Nikkol HCO-40      200.0                                                      TOTAL              450.0                                        4.4.          Cyclosporin (e.g. Ciclosporin)                                                                   50.0                                              (1.1)    Transcutol         100.0                                             (3.1.1)  Cremophor RH 40    94.0                                              (3.2.1)  Labrafil M 1944    31.0                                                       TOTAL              275.0                                        ______________________________________                                    

Equivalent compositions may be prepared by replacing Transcutol in 4.1,4.2 or 4.4 with the same or equivalent amount of Glycofurol, or theGlycofurol in 4.3 with the same or equivalent amount of Transcutol.

EXAMPLE 5 Preparation of Oral Dosage Forms: Thickened EmulsionPre-concentrate Type

    ______________________________________                                                                     QUANTITY                                         5.1. COMPONENT               (mg/capsule)                                     ______________________________________                                                  Cyclosporin (e.g. Ciclosporin)                                                                   50.0                                             (1.1)     Transcutol         80.0                                             (3.1.1)   Cremophor RH 40    75.0                                             (3.2.1)   Labrafil M 1944 CS 25.0                                             (4.1)     Eudragit E         50.0                                                       TOTAL              280.0                                            ______________________________________                                    

(3.1.1), (3.2.1) and (4.1) are combined with and dissolved in (1.1) withstirring and light warming. Cyclosporin is then added with light warmingand further stirring and the product filled into size 2 hard-gelatincapsules and sealed.

The following compositions can be prepared analogously for filling intosize 1 or 2 hard gelatin capsules as appropriate:

    ______________________________________                                                                  QUANTITY                                            COMPONENT                 (mg/capsule)                                        ______________________________________                                        5.2.         Cyclosporin (e.g. Ciclosporin)                                                                    100.0                                             (1.1)   Transcutol          180.0                                             (3.1.4) Pluronic F68        140.0                                             (3.1.6) Sodium laurylsulphate                                                                             5.0                                               (4.2)   Sodium carboxymethylcellulose                                                                     25.0                                                      TOTAL               350.0                                        5.3.         Cyclosporin (e.g. Ciclosporin)                                                                    50.0                                              (1.1)   Transcutol          163.0                                             (3.1.1) Cremophor RH 40     100.0                                             (3.2.1) Labrafil M 1944 CS  35.0                                              (4.3)   Kollidon 30         72.0                                                      TOTAL               420.0                                        ______________________________________                                    

Equivalent compositions may be prepared by replacing the Transcutolcomponent with Glycofurol in the same or equivalent amount.

EXAMPLE 6 Preparation of Topical Dosage Forms: Emulsion Type

The following are prepared by intimate admixture of the indicatedingredients analogously to examples 2 and 5 above, to provide ointmentpreparations suitable for topical application:

    ______________________________________                                        COMPONENT               % BY WEIGHT                                           ______________________________________                                        6.1.         Cyclosporin (e.g. Ciclosporin)                                                                   0.1                                                (1.1)   Transcutol         15.0                                               (3.1.1) Cremophor RH 40    5.0                                                (3.2.1) Labrafil M 213     15.0                                               (3.2.5) Glycerolmonostearate                                                                             10.0                                               (6.2)   White petrolatum   54.9                                          6.2.         Cyclosporin (e.g. Ciclosporin)                                                                   0.1                                                (1.2)   Glycofurol         15.0                                               (3.2.5) Glycerolmonostearate                                                                             8.0                                                (6.1)   Mineral oil        39.0                                               (6.1)   White petrolatum   37.9                                          ______________________________________                                    

EXAMPLE 7 Preparation of Oral Dosage Forms: Sugar Ester Type

    ______________________________________                                        INGREDIENT               (mg/capsule)                                         ______________________________________                                        7.1.         Cyclosporin (e.g. Ciclosporin)                                                                    50.0                                              (1.1)   Glycofurol          100.0                                             (5)     Saccharose monolaurate L-1695*                                                                    312.5                                                     TOTAL               462.0                                        7.2.         Cyclosporin (e.g. Ciclosporin)                                                                    50.0                                              (1.1)   Transcutol          80.0                                              (5)     Saccharose monolaurate L-1695*                                                                    312.5                                                     TOTAL               442.5                                        7.3.         Cyclosporin (e.g. Ciclosporin)                                                                    50.0                                              (1.1)   Glycofurol          100.0                                             (5)     Saccharose monolaurate L-1695*                                                                    312.5                                             (4.2)   Klucel LF           50.0                                                      TOTAL               512.5                                        ______________________________________                                         (*Product commercially available from MitsubishiKasei Food Corp., Tokyo       104, Japan: HLBvalue = at least 12.3: lauryl ester residue purity = at        least 95%: M.P. = ca. 35° C.: decomposition at ca. 235° C.:     surface tension of 0.1% by weight aqueous solution = ca. 72.0 dyn/cm at       25° C.)                                                           

The composition of example 7.1 is prepared by dissolving cyclosporin and(5) with stirring and warming over an oil bath at 100° C. in component(1.1). The composition of examples 7.2 and 7.3 are prepared analogously.

The obtained compositions are filled, with warming, into hard gelatincapsules size 1 (compositions 7.1 and 7.2) or 0 (composition 7.3).

Utility of compositions in accordance with the invention may be shown inanimal or clinical trials, for example performed as follows:

    ______________________________________                                        BIOAVAILABILITY STUDY FOR COMPOSITIONS IN                                     ACCORDANCE WITH THE INVENTION IN THE DOG                                      ______________________________________                                        a)  Test compositions                                                             COMPOSITION I     as per example                                                                            1.1                                             COMPOSITION II    as per example                                                                            1.2                                             COMPOSITION III   as per example                                                                            1.6                                             COMPOSITION IV    as per example                                                                            2.1                                             COMPOSITION V     as per example                                                                            2.2                                             COMPOSITION VI    as per example                                                                            4.4                                             COMPOSITION VII   as per example                                                                            5.3                                         b)  Test method                                                                   Groups of 8 beagle dogs (male, ca. 11-13 kg) are used.                        Animals receive no food within 18 hours of administration                     of test composition but are allowed free access to water until                administration. Test compositions are administered by gavage,                 followed by 20 ml NaCl 0.9% solution. The animals are                         allowed free access to food and water three hours after                       administration of test composition.                                           2 ml blood samples (or 5 ml for the blank) are taken from                     the vena saphena and collected in 5ml plastic tubes containing                EDTA at -15 min. (blank), 30 min., and 1, 1.5, 2, 3, 4, 6,                    8, 12 and 24 hours post administration. Blood samples are                     stored at -18° C. pending assay.                                       Blood samples are analysed by RIA. Areas under the blood                      drug concentration versus time curves are calculated by the                   trapezoidal rule. Analysis of variance is performed with                      respect to AUC (area under curve), Cmax (maximum                              concentation) and Tmax (time of maximum).                                 c)  Results                                                                       Calculated average AUC (In ng hr./ml.sup.-1) and Cmax (in                     ng/ml.sup.-1) values from typical trial runs are shown in the                 following table, together with calculated variation in response               between test animals receiving the same composition                       ______________________________________                                            (CV).                                                                                 AUC                                                               COMPOSITION (0-24h) CV (%)     Cmax  CV %                                     ______________________________________                                        I           2969    46.1       655   42.4                                     II          3315    35.9       606   29.0                                     III         3392    33.0       623   25.0                                     IV          4010    35.1       756   30.0                                     V           2769    27.8       469   21.7                                     VI          2375    40.3       518   29.2                                     VII         2329    23.1       470   36.1                                     ______________________________________                                    

As will be seen from the above table, compositions in accordance withthe invention exhibit high bioavailability (AUC and Cmax.) coupled withrelatively low variability in subject response both for AUC and Cmax.

Comparable advantageous results may be obtained employing othercompositions in accordance with examples 1,2,4,5 and 7 herein, inparticular the compositions of example 1.

The advantageous properties of the compositions of the invention on oraladministration may also be demonstrated in clinical trials, e.g.performed as follows:

Trial subjects are adult volunteers, e.g. professionally educated malesof from 30 to 55 years. Trial groups suitably comprise 12 subjects.

The following inclusion/exclusion criteria are applied: Inclusion:Normal screening ECG; normal blood-pressure and heart rate; bodyweight=50-95 kg. Exclusion: Clinically significant intercurrent medicalcondition which might interfere with drug absorption, distribution,metabolism, excretion or safety; symptoms of a significant clinicalillness in the two-week pre-trial period; clinically relevant abnormallaboratory values or electrocardiogram; need for concomitant medicationduring the entire course of the study; administration of any drug knownto have a well-defined potential toxicity to a major organ system withinthe previous 3 months; administration of any investigational drug within6 weeks prior to entry into the trial; history of drug or alcohol abuse;loss of 500 ml or more blood within the past 3 month period; adversedrug reaction or hypersensitivity; history of allergy requiring drugtherapy; Hep.-B/HIV-positive.

Complete physical examination and ECG is performed pre- and post-trial.The following parameters are evaluated within 1-month periods pre- andpost-trial:

Blood:--red blood cell count, haemoglobin, hematocrit, erythrocytesedimentation, white blood cell count, smear, platelet count and fastingglucose;

Serum/plasma--total protein and electrophoresis, cholesterol,triglycerides, Na⁺, K⁺, Fe⁺⁺, Ca⁺⁺, Cl⁻ creatinine, urea, uric acid,SGOT, SGPT, -GT, alkaline phosphatase, total bilirubin, α-amylase;

Urine--pH, microalbumin, glucose, erythrocytes, ketone bodies, sediment.Creatinine clearance is also determined 1-month prior to trial entry.

Subjects each receive trial compositions in randomised sequence.Compositions are administered orally, once to a total dose of 150 mgcyclosporin, e.g. Ciclosporin, and at least 14 days are allowed betweeneach administration.

Administration is performed in the morning after an overnight fast of 10hrs. with only water allowed. Only caffein-free beverages are permittedwithin the 24 hr. period following administration. Subjects are notallowed to smoke within the 12 hr. period following administration.Subjects receive a standardised lunch 4 hrs. following administration.

Blood samples (2 ml) are taken 1 hr. prior to administration andpost-administration at 0.25, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 6,9, 12, 14, 24, 28 and 32 hrs.. For determination of creatinine 2 mlblood samples are taken immediately prior to administration and at 12,24 and 48 hrs. post-administration. Samples for cyclosporindetermination are collected in two EDTA coated polystyrene tubes (1 mleach) at each time point and are deep frozen at -20° C. after gentleagitation. Cyclosporin is assayed in whole blood using RIA with specificand/or non-specific MAB assay-detection limit in both cases=ca. 10ng/ml.

In one such trial COMPOSTION I above in accordance with the invention(hard gelatin encapsulated form) is compared with COMPOSITION X.

    ______________________________________                                        COMPOSITION X [COMPARATIVE (ART) COMPOSITION]                                 Unit dosage form (soft gelatin capsule) comprising                            ______________________________________                                        Ciclosporin         50 mg                                                     Labrafil           150 mg                                                     Ethanol             50 mg                                                     Maize oil          213 mg                                                     Total              463 mg/dosage.                                             ______________________________________                                         (= current Sandimmun oral, drink solution)                               

In a trial performed in this manner a bioavailability level of 149.0%(±48) is recorded for COMPOSITION I as compared with COMPOSITION X (forwhich bioavailability achieved is set as 100%). AUC values (0-32 hrs.ng.h/ml) and Cmax. values (ng/ml) established for COMPOSITION I are 2992(±627) and 882 (±18) respectively as compared with 2137 (±606) and 515(±180) for COMPOSITION X.

FIGS. 3 and 4 attached provide superimposed graphical representationsfrom such a trial of whole blood Ciclosporin concentrations recorded forall 12 trial participants following single oral administrations ofCOMPOSITION I (FIG. 3) and COMPOSITION X (FIG. 4), each in an amountproviding a Ciclosporin dosage of 150 mg, as determined by specificmonoclonal RIA. Blood concentration (in ng/ml) is recorded vertically,and time (in hrs.) horizontally.

Comparison of FIGS. 3 and 4 clearly demonstrates the marked reduction invariability of inter-subject response with respect to bioavailabilityparameters recorded, on administration of COMPOSITION I as compared withCOMPOSITION X. The determined coefficient of variation [(standarddeviation/mean value).sub.× 100] with respect to Cmax. for COMPOSITION Xis 35% as compared with a value of only 20% for COMPOSITION I.

Similar or equivalent results may be obtained following oraladministration of other compositions in accordance with the invention,e.g. as herein described in the examples, in particular the compositionsof example 1.

IN VIVO TESTING FOR TOPICAL FORMS Allergic Contact Dermatitis Test inthe Guinea Pig

Guinea pigs (Hartley, male, 400-500 g) are sensitised by application of50 μl, 0.5% DNFB in acetone/olive oil (4:1) applied to marked areas onthe shaven, left and right flank. This second challenge exposure inducesan allergic inflammation, leading to reddening and cellular infiltration(thickening) of the skin. Test composition (e.g. in accordance withexample 3,6.1 or 6.2 above) in an amount of from 200-250 mg is appliedwith a spatula to the DNFB treated area of the right flank. The leftflank is similarly treated with placebo as control. Application of testcomposition/placebo is effected 5× at intrvals of 20 mins., 8 hrs., 24hrs., 32 hrs., and 48 hrs., after the challenge. Skin thickness at thesite of application is determined before each application, and again 8hrs. after the last application, by raising the skin into a fold andmeasuring the thickness of this. Degree of reddening or inflammation isalso estimated visually on a scale of from 0 to 4 . Efficacy of testpreparation in preventing inflammatory response is determined bycomparison with results recorded for placebo treated flanks.

In the above test method substantial reduction in skin thickening ascompared with placebo are achieved following first application of testcomposition, e.g. in accordance with examples 3,6.1 or 6.2, continuingthrought treatment until completion of the experiment. The followingresults are recorded for the composition of example 3.

    ______________________________________                                        TIME AFTER                                                                    CHALLENGE (HRS)                                                                             8        24    32     48  56                                    ______________________________________                                        % INHIBITION OF                                                                             56       68    76     75  73                                    SKIN THICKNESS/                                                               US PLACEBO                                                                    CONTROL                                                                       ______________________________________                                    

We claim:
 1. A pharmaceutical composition comprising a cyclosporin asactive ingredient,1) a hydrophilic phase component comprising1.1) apharmaceutically acceptable di- or partial-ether of the formula

    R.sub.1 --[O--(CH.sub.2).sub.2 ].sub.x --OR.sub.2

wherein R₁ is C₁₋₅ alkyl or tetrahydrofurfuryl, R₂ is hydrogen, C₁₋₅alkyl or tetrahydrofurfuryl, and X is an integer from 1 to 6, or1.2)1,2-propylene glycol; 2) a lipophilic phase component; and 3) asurfactant;wherein said composition is a microemulsion pre-concentrate,which upon dilution with water to a ratio of 1:1 parts by weightpre-concentrate to water or more of said water, is capable of providingan oil-in-water microemulsion having average particle size of less thanabout 1,000 Å.
 2. A composition of claim 1 wherein said ratio is 1:5parts by weight pre-concentrate to water or more of said water.
 3. Thecomposition according to claim 1 wherein said hydrophilic phasecomponent comprises 1,2-propylene glycol.
 4. The composition accordingto claim 3 wherein said hydrophilic phase component comprises a C₁₋₅alkanol as additional hydrophilic phase component.
 5. The compositionaccording to claim 4 wherein said C₁₋₅ alkanol is ethanol.
 6. Thecomposition according to claim 1 wherein said lipophilic phase (2)comprises a fatty acid triglyceride.
 7. The composition according toclaim 1 wherein said surfactant (3) comprises a polyoxyethyleneglycolated natural or hydrogenated vegetable oil.
 8. The compositionaccording to claim 1 wherein said surfactant (3) comprises an additionalco-surfactant.
 9. The composition according to claim 8 wherein saidsurfactant (3) comprises a polyoxyethylene glycolated natural orhydrogenated vegetable oil as surfactant and a monoglyceride as saidco-surfactant.
 10. The composition according to claim 1 which furthercomprises a thickening agent.
 11. The composition according to claim 1adapted for oral administration.
 12. The composition according to claim11 in unit dosage form.
 13. The composition according to claim 12 in agelatin capsule.
 14. The composition according to claim 11 comprisingfrom 5 to 20% by weight of said cyclosporin based upon the total weightof the composition.
 15. The composition according to claim 1 containing1,2-propylene glycol in an amount of from 3 to 45% by weight based uponthe total weight of the composition.
 16. The composition according toclaim 11 wherein the ratio of said cyclosporin to 1,2-propylene glycolis from 1:0.5 to 1:3 parts per weight.
 17. The composition according toclaim 1 wherein said lipophilic phase component (2) is present in anamount of from 2 to 45% by weight based on the total weight of thecomposition.
 18. The composition of claim 11 containing 1,2-propyleneglycol and wherein the ratio of said lipophilic phase component (2) to1,2-proppylene glycol is from 1:0.15 to 1:6 parts by weight.
 19. Thecomposition of claim 11 wherein said component 3) is present in anamount of from 20 to 90% by weight based on the total weight of saidcomposition.
 20. The composition of claim 11 wherein the ratio of saidcyclosporin to said component 3) is from 1:1 to 1:10 parts by weight.21. The composition according to claim 1 comprising from 0.05 to 15% byweight of said cyclosporin based on the total weight of saidcomposition, wherein said composition is in a form suitable for topicalapplication.
 22. The composition according to claim 21 comprising from0.1 to 10% by weight of said cyclosporin based on the total weight ofsaid composition.
 23. A pharmaceutical microemulsion compositioncomprising water and the composition of claim
 1. 24. The composition ofclaim 1, wherein said cyclosporin is Ciclosporin.
 25. The composition ofclaim 1 wherein said cyclosporin is [Nva]² -Ciclosporin.
 26. An oralpharmaceutical composition comprising Ciclosporin or [Nva]² -Ciclosporinas an active ingredient;1) a hydrophilic phase component which comprisesa pharmaceutically acceptable C₁₋₅ alkyl di-or partial-ether, ortetrahydrofurfuryl di-or partial-ether, of a mono- or poly-oxy-C₂₋₁₂-alkanediol, or 1,2-propylene glycol; 2) a lipophilic phase componentwhich comprises a fatty acid triglyceride; and 3) a surfactant whichcomprises a polyoxyethylene glycolated natural or hydrogenated vegetableoil and monoglyceride;wherein said composition is a microemulsionpre-concentrate capable, on contacting with water, of forming anoil-in-water microemulsion having an average particle size of less than1,000 Å.